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Glossary of Terminology: T

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Number of records found : 193


t-test - a statistical procedure for testing the difference between two or more means. It is used for estimating the probability that the means have been drawn from the same or different populations

t. - according to; on the evidence of (teste)

t. c. - in the volume cited (tomus citate)

table reef - an isolated flat-topped coral reef which reaches the surface but lacks a lagoon

Image of <i>(Acropora)</i> coral

Coral (Acropora) having a tabulate shape.


tabulate - having a flat surface

tactile - pertaining to information, interpretations, and behavior derived from the sense of touch

taeniform - ribbon-like; elongate, compressed and deep-bodied

tagging - an identification system involving various methods (fin clipping, coloring, biotelemetry, radioactive markers, tattooing, branding, tagging, etc.), used for individual identification and for studies on movement, growth and other biological activities;  also called "marking"

talus slope - a synonym of reef base

tandem repeats - in molecular genetics, multiple copies of the same nucleotide base sequences lying in series

Image of diver entering water

A NOAA diver breathing compressed air from the steel scuba tank (or cylinder) attached to his BCD (buoyancy control device). The diver is entering the water using the giant step technique. (Photo: NOAA National Undersea Research Program)


tank - a hollow steel or aluminum cylinder, used to contain compressed air or other breathing gas mixtures used by scuba divers for an air supply; also called a cylinder or bottle

taphonomy - the study of everything that happens to an organism’s body after it dies; includes probable cause and manner of death, movement of the body, chemical and physical alteration, burial, decomposition, diagenesis and fossilization

tar ball - a dense, black sticky sphere of hydrocarbons formed from weathered oil

target - in genomics, the DNA or RNA being hybridized to a microarray; for diagnostic tests, the molecule or nucleic acid sequence that is being sought in a sample

tau - the third charged lepton (in order of increasing mass), with electric charge -1

tautonymy - in taxonomy, the use of the same word for the name of a genus-group taxon and for one of its included species or subspecies

tawny - brownish yellow color

taxis - an innate behavioral response to a directional stimulus (a stimulus from a particular direction) whereby the organism either moves toward (positive taxis) or away (negative taxis) from the stimulus

taxocene - a taxonomically related set of species within a community that have similar ecological functions

taxon - a taxonomic group or entity

taxonomic group - a taxon with all its subordinate taxa and their individuals; e.g. the taxonomic group Crustacea consists of all crustaceans and their taxa

taxonomic group - a taxon with all its subordinate taxa and their individuals; e.g., the taxonomic group Crustacea consists of all crustaceans and their taxa

taxonomic key - a tabulation of diagnostic characters of taxa in dichotomous couplets to facilitate rapid identification

taxonomy - the science and methodology of classifying organisms based on physical and other similarities. Taxonomists classify all organisms into a hierarchy, and give them standardized Latin or Latinized names. There are seven main levels of classification in the hierarchy. They are, from most to least inclusive: Kingdom; Phylum (or Division for algae, fungi, and plants); Class; Order; Family; Genus; and Species. Taxonomists describe new species, classify organisms, and study speciation, the evolution of new species

teal - greenish blue color

technology - the creation of products and processes for the purpose of improving human chances for survival, comfort level, and quality of life

tectal - pertaining to the roof of a structure, e.g. the top of the head or brain

teleost - a large group of fishes (infraclass Teleostei) which contains most of the bony fishes

telepresence - the use of telecommunications technology to give the appearance of an individual being present at a location other than the actual location of that individual

telolecithal - an egg cell in which the yolk is not evenly distibuted throughout the cytoplasm, but is concentrated in one location, and cleavage is incomplete, e.g., a bird egg

telomere - the terminal part of a eukaryotic chromosome. These specialised structures are involved in the replication and stability of linear DNA molecules. In vertebrate cells, each telomere consists of thousands of repetitive copies of the same DNA sequence. Telomeres shorten each time a cell divides; when one or more telomeres reaches a minimum critical length, cell division stops, signaling cell senescence. This mechanism limits the number of times a cell can divide

Graphic of lobster external structure

The telson, flanked by uropods, is the central part of the tail fan. (Graphic: Maine Department of Marine Resources)


telson - the terminal joint or movable piece at the end of the abdomen of crustaceans; middle piece of the tail fan

temperate - region in which the climate undergoes seasonal change in temperature and moisture. Temperate regions of the earth lie primarily between 30 and 60 degrees latitude in both hemispheres

template - a molecule that serves as the pattern for synthesizing another molecule ; in the process of replication or transcription, the strand of DNA that serves as the source of information

temporary threshold shift - in mammals, a temporary increase in the threshold of hearing (minimum intensity need to hear a sound) at a specific frequency that returns to its pre-exposure level over time

tendril - a slender elongated thread-like organ which may cling to objects for support

tendriliform - having the form or shape of a tendril

Image of tentacles of sea anemone

Tentacles of a sea anemone. Each tentacle contains stinging cells (nematocysts) used for defense and food capture. (Photo: Dr. Anthony Picciolo)


tentacle - a finger-like evagination of the body wall. Tentacles surround the mouths of coral polyps, anemones and other invertebrates. They are used for capturing prey, defense, reproduction, gas exchange, and light absorption

tentacle-tube-foot suspension feeder - a suspension feeder that traps particles on distinct tentacles or tube feet (in echinoderms)

tentacular lobe - a lobe at the point of insertion (beginning) of a septum

tentacular sheath - one of the two cavities in the sides of the body of ctenophores (comb jellies) into which the tentacles can be withdrawn

terabyte - a measure of data size. A terabyte of data is equivalent to 1,000 gigabytes of data or 1,000,000 megabytes of data. One petabyte equals 1,000 terabytes

teratogen - a chemical or other factor that specifically causes abnormalities during embryonic growth and development

terete - round in cross-section and tapering

tergite - a hard plate (sclerite) forming one of the constituents of the dorsal exoskeleton (tergum) of an animal, such as an arthropod

tergum - the back of an animal

terminal - at the end position

terminal male - in fishes, a supermale; the dominant male

termination codon - a codon whose function is to stop polypeptide assembly

terminator - a sequence of DNA bases that stops RNA polymerase from synthesizing RNA

terminus - the end

ternary name - in taxonomy, the trinomen

terpenoid - a class of organic compound produced by soft corals for defense and for aggressive colonization of new substrates

territoriality - the defense of a given area

territory - an area over which an animal establishes jurisdiction. The area is defended and no other individuals of the same species, and often of other species, are allowed inside, except for prospective breeding partners during a reproductive bout

Image of blenny

A tessellated blenny. (Photo: NOAA)


tessellated - a checkered appearance

Image of sea urchin test

Dorsal view of sea urchin test.


test - shell or hard outer covering of echinoderms and ascidians

test animal - an individual used for experimental research purposes

tetraspore - a haploid spore in the red algae life cycle which is the meiotic product of the tetrasporangium of a diploid tetrasporophyte. The tetraspores are released, settle, and grow into gametophytes

tetrasporophyte - diploid phase in the life cycle of red algae which produces haploid tetraspores.The tetrasporophyte is the site of meiosis, more specifically, the tetrasporangia where haploid tetraspores are produced. These tetraspores are released, settle, and grow into the gametophyte, completing the basic red algal life history

tetraxon - in sponges, a spicule with four rays

Image of chef preparing fugu

A specially licensed Japanese chef prepares fugu, the ever-so-slightly tainted fillet of the extremely poisonous blowfish, whose internal organs contain tetrodotoxin.


tetrodotoxin (TTX) - tetrodotoxin (TTX) is an especially potent marine neurotoxin, named after the order of fish from which it is most commonly associated, the Tetraodontiformes (includes the puffers, porqupine fish, blowfish, cowfish, boxfish).The toxin appears in high concentrations in the gonads, liver, intestines and skin of pufferfish. The fatality rate when injested may be as high as 60 percent. Tetradotoxin is more than 10,000 times deadlier than cyanide. Other marine and terrestrial organisms have been found to store TTX, for example, the Australian blue-ringed octopus, parrotfish, triggerfish, gobies, angelfish, ocean sunfish, globefish, seastars, starfish, xanthid and other crabs, a horseshoe crab, a number of marine snails, flatworms, tunicates, ribbonworms, mollusks and marine algae (Jania spp.) Terrestrial organisms include the Harlequin frogs (Atelopus spp.), three species of California newt and other eastern salamanders

thallus - the vegetative body of a plant or alga that is not differentiated into organs, such as roots,stems and leaves

thanatocoenosis - an assemblage of organisms or their parts brought together after their deaths, as for example, by flowing water; 'death assemblage'

theca - the calcareous wall of the corallite

thelytoky, thelytokous - parthenogenetic production of females from unfertilized eggs; reproduction that is exclusively female with no male contribution to the young

theoretical probability - the chances of events happening as determined by calculating results that would occur under ideal circumstances

theory - a comprehensive explanation of a given set of data that has been repeatedly confirmed by observation and experimentation and has gained general acceptance within the scientific community

thermal stress anomaly (TSA) - an area of the ocean surface which is experiencing warmer sea surface temperatures (SSTs) than the typical maximum temperature reached at that location. The typical maximum temperature, which generally occurs in late summer, is important because this is the highest temperature to which corals in a particular location are accustomed. So, when the SST exceeds this by some threshold (typically one degree C) corals are in danger of bleaching. Many factors such as salinity, insolation, winds, and local currents play a role in coral reef bleaching, but clearly extreme SSTs are a critical factor; also called "hotspots"

thermocline - the region below the surface layer of the ocean or lake, where the temperature gradient increases abruptly (i.e. where temperature decreases rapidly with increasing depth). A thermocline may reach the surface and become a front. It is usually an ecological barrier and its oscillations have significant consequences on population distribution and ocean productivity

thermohaline circulation - the density-driven convective circulation system of the world's oceans. Warm Atlantic water moves northward along the axis of the Gulf Stream, and evaporation increases water density while releasing heat to the colder atmosphere in the North Atlantic. Once significantly dense, the water sinks into the deep ocean, forming a downward limb of a giant conveyor-like circulation that extends around the world's oceans

thermoreceptor - a neurological receptor that detects changes in temperature

thigmotactic - responding to touch or outer surface contact

Third Party Annotation (TPA) Sequence - a database designed to capture experimental or inferential results that support submitter-provided annotation for nucleotide sequence data that the submitter did not directly determine but derived from GenBank primary data

thirtyS (30S) - 30S is the smaller subunit of the 70S ribosome of prokaryotes. It is a complex of ribosomal RNA and ribonucleoproteins which functions in messenger RNA (mRNA) translation. It includes the subunit 16S, which is composed entirely of ribosomal RNA

thoracic - pertaining to the chest area

thorax - the central region of a crustacean body

Diagram of thymine

Diagram of the chemical structure of thymine, one of the four nitrogenous bases in DNA.


thymine - one of the four bases in DNA that make up the letters ATGC, thymine is the "T". The others are adenine, guanine, and cytosine. Thymine always pairs with adenine

tidal channel - a channel that dissects the tidal flat surface. It is formed and maintained by tidal currents

tidal current - a horizontal movement of the water caused by gravitational interactions between the Sun, Moon, and Earth

tidal delta - a delta formed at both sides of a tidal inlet

tidal flat - a marsh or sandy or muddy coastal flatland which is covered and uncovered by the rise and fall of the tide

tidal inlet - a waterway from the open ocean into a lagoon

tidal pool - an area in the littoral zone that retains sea water at a low tide because of a depression or arrangement of rocky substrate

Image of tide swamping pier in storm

High tide combined with a storm threaten a pier. (Photo: Mary Hollinger)


tide - the periodic rising and falling of the water that results from the gravitational attraction of the moon and sun acting on the rotating earth

tide gauge - a device for measuring the height (rise and fall) of the tide; especially an instrument for automatically making a continuous graphic record of tide height versus time

tide tables - tables which give daily predictions of the times and heights of high and low waters. These predictions are usually supplemented by tidal differences and constants through which predictions can be obtained for numerous other locations

tidelands - the zone between the mean high water and mean low water lines. It is identical with intertidal zone (technical definition) when the type of tide is semi-diurnal or diurnal

TIFF (Tag Image File Format) - a common format for exchanging raster graphics (bitmap) images between application programs, including those used for scanner images

tinctorial - of or relating to staining or coloring

Tisler Reef - a deep water Lophelia reef located in the Skagerrak, the submarine border between Norway and Sweden, at depths of 74 to 155 m. It has the world's only known yellow Lophelia pertusa corals

tissue - a group of cells with a specific function in the body of an organism. Tissues are composed of nearly identical cells and their products, and are organized into larger units called organs

tom. - volume (tomus)

tombolo - a land form such as a spit or bar which forms an isthmus between an island and a mainland shore, or between two islands

topodeme - a deme (a local interbreeding population) occupying any specified geographical area

topographic map - a map containing contours indicating lines of equal surface elevation (relief)

topotype - in taxonomy, a specimen collected at the type locality

topotypical population - in taxonomy, a population occurring at the type locality

Image of tornaria larva

Young tornaria of Balanoglossus biminiensis. (Photo: University of Saskatchewan Archives)


tornaria larva - a ciliated, free-swimming pelagic larva of a hemichordate

torpor - a dormant state

torsion - twisting of the body during development so that the posterior of the body takes an anterior position over the head

total dissolved solids (TDS) - the amount of dissolved substances, such as salts or minerals, in water remaining after evaporating the water and weighing the residue

Towed Optical Assessment Device (TOAD) - a device employing videography used chiefly at night on the NOWRAMP cruises to the Northwestern Hawaiian Islands. TOAD consists of a video camera and lights on a frame designed to be towed just above the substrate. The video is used to certify or ground truth acoustic habitat sensing. Specifically, the TOAD videos show the composition of the bottom in a few locations, such as sand, rubble, sea grass, coral, etc. It allows interpretation of broad area acoustic data by comparing it to the video information

towfish - an instrument, e.g., a side scan sonar, towed behind a ship

ToxiBan ® Suspension Activated Charcoal - a brand of activated charcoal used in the treatment of poisoning by most organic chemicals

toxicant - any substance which is potentially toxic

trabeculum - in corallites, one of many rods or axial structures composed of fibrous tufts (sclerodermites), which form teeth along the upper septal margin

trade winds - a system of relatively constant low level winds that occur in the tropics. The trade winds blow from the northeast to the equator in the Northern Hemisphere and from the southeast to the equator in the Southern Hemisphere

trait - a genetic feature or characteristic that may be passed down from one generation to the next

transcription - the process by which the genetic information encoded in a linear sequence of nucleotides in one strand of DNA is copied into an exactly complementary sequence of mRNA (messenger RNA). The mRNA then carries this information to the cytoplasm of the cell, where it serves as the blueprint for the manufacture of a specific protein

transcription unit - a stretch of DNA transcribed into an RNA molecule

transcriptome - the set of all RNA molecules, including messenger RNA (mRNA), ribosomal RNA (rRNA), transfer RNA (tRNA), and non-coding RNA produced in one or a population of cells; a collection of all the transcripts present in a given cell

transcriptomics - the discipline of molecular biology that is concerned with the study of messenger RNA (mRNA) molecules produced in an individual or population of a particular cell type

Graphic of transducer

Split beam transducer receives echoes with four different quadrants (Graphic: American Fisheries Society)


transducer - the electromechanical component of a sonar system that is mounted underwater and converts electrical energy to sound energy and vice versa

transduction - transfer of genetic material from one cell to another by means of a virus or phage vector

Image of NOAA divers

NOAA divers collect data along a transect line.


transect - a line used to survey the distribution of organisms or substrate across a given area. Sample plots or points are established along the transect for collecting data

transfection - infection of a cell with nucleic acid from a virus, resulting in replication of the complete virus; gene transfer into eukaryotic cells

transfer RNA (tRNA) - short-chain RNA molecules present in the cell, in at least 20 varieties. Each variety is capable of combining with a specific amino acid, and attaches the correct amino acid to the protein chain that is being synthesized at the ribosome of the cell, according to instructions coded in the mRNA

transforming gene - a gene that causes normal cells to change into cancerous tumor cells; also called an 'oncogene'  

transgenic - having genetic material (DNA) from another species. This term can be applied to an organism that has genes from another organism

translation - in genetics, the process whereby genetic information coded in mRNA (messenger RNA) directs the formation of a specific protein at a ribosome in the cytoplasm

translocation - a conservation technique whereby individuals or populations are moved to another area with similar habitat

transmissometer - an instrument for measuring transmission of light through a fluid

transposon - a DNA sequence of nucleotides that can insert itself at a new site in the genome

transverse - crosswise

trauma - any sudden physical injury or damage to an organism caused by an external force or violence. Trauma is also used to describe severe emotional or psychological shock or distress

traumagenic device - any part of an organism which is concerned with the causation of physical injury to another, such as teeth, spines, darts, rasping organs, beak bites, etc

trawler - a fishing vessel that tows an open-mouthed fishing net drawn along the sea bottom or in the water column

tree of life - the tree-like representation of the evolutionary history of all living and extinct organisms

trematodiasis - an infestation or infection with trematodes, a class within the phylum Platyhelminthes (Trematoda), that contains parasitic flatworms commonly referred to as "flukes".

trend analysis - the analysis of changes in numerical data over time in order to study any pattern or trend represented in them

trial and error learning - a form of associative learning. Trial and error learning occurs when an animal connects its own behavior with a particular environmental response. If the response has a positive reinforcement, or it is favorable to the animal, the animal will repeat the behavior in order to receive the same response again, possibly to receive a reward. If the response is unfavorable, such as causing pain, the animal will avoid the behavior

Image of sponge spicules

Microscopic triaxon spicules in a sponge. (Photo: NOAA)


triaxon - in sponges, a spicule with three rays

tribe - a taxonomic group that is between a genus and a subfamily

trichocyst - a stinging or grasping organelle in the outer cytoplasm of protists, especially ciliates. It consisting of a hair-like filament that can be discharged suddenly from a minute capsule

trichogyne - receptive elongation of the carpogonium (female reproductive structure) in red algae where male gametes become attached

trifurcate - dividing into three parts

triggerfish - any of several species of tropical coral reef fishes in the order Tetraodontiformes, family Balistidae, with laterally compressed bodies, heavy scales, and tough skins. Triggerfishes are named for the mechanism of the three spines of their first dorsal fin. When the fish is alarmed the first of these spines is locked upright by the second and drops only when the latter is pressed like a trigger. The function of this reaction is to lock the fish firmly in a mass of coral when attacked. Triggerfishes have powerful, chisel-like teeth adapted for cracking the coral and mollusks upon which they feed

triglyceride - a complex molecule which is the main component of dietary and body fat. It is made up of a combination of glycerol and three fatty acids

trihedral - with three surfaces, e.g. the body of a trunkfish

Image of divers at app. 200 feet depth.

Marine scientists breathing trimix working on a transect line in order to collect sponge and water samples at a depth of approximately 60 m (200 ft). (Photo: NOAA National Undersea Research Program)


trimix - a breathing gas mixture of helium, oxygen, and nitrogen. By using trimix, it is possible for divers to descend to hundreds of feet without suffering from toxic partial pressures of oxygen (which increases with depth), and also reduces the effect of nitrogen narcosis

trinomen - in taxonomy, the combination of a generic name, a specific name, and a subspecific name, that together constitute a scientific name subspecies

triplet - in genetics, a sequence of three nucleotides of DNA which specifies an amino acid.

tripton - the nonliving particulate matter in bodies of water

tritoniid - a member of a family of nudibranchs (Tritoniidae) which feed on soft corals, gorgonians, and other anthozoans. A characteristic common to the tritoniids are the dorsilateral branched cerata, used as gills and located in the edges of the dorsal surface

triturate - to grind or masticate

Image of trocophore larva

The trochophore larva of a marine worm. (Photo: University of Saskatchewan Archives)


trochophore larva - the ciliated planktonic larva of many invertebrates, including polychaete worms, mollusks, and rotifers

troglobite - an obligate cave dweller

Graphic of vessel trolling

Fishing vessel trolling for tuna. (Graphic: NOAA)


trolling - a fishing method where lures or baits attached to lines are towed behind a slowly moving boat

trophic - related to or functioning in nutrition

trophic dynamics - the complex biological processes whereby energy and matter are passed up to successive levels of food webs

trophic group - a group of organisms consuming resources from a similar level in the energy cycle

trophic level - a classification system of organisms according to their means of obtaining nutrition. A segment of the food chain in which all organisms obtain food and energy in basically the same manner (e.g., photosynthesis, herbivory, or carnivory) and in which all organisms are the same number of links from the photosynthetic segment

tropical - region in which the climate undergoes little seasonal change in either temperature or rainfall. Tropical regions of the earth lie primarily between 30 degrees north and south of the equator

tropical depression - a mass of thunderstorms and clouds generally with a cyclonic wind circulation of between 20 and 34 knots

tropical disturbance - an organized mass of thunderstorms with a slight cyclonic wind circulation of less than 20 knots

Tropical Ocean Coral Bleaching Indices - indices of selected coral reef sites/regions (maintained by NOAA/NESDIS) that present satellite-obtained measurements of relevance to coral reef ecosystems

tropical storm - a tropical cyclone with maximum winds less than 34 m/sec (75 mile per hour)

trumpetfish - any of a family of tropical reef fishes (Aulostomidae), recognised by its long body, tubular snout with minute teeth, its chin barbel, and a series of short dorsal spines. A carnivore, It often approaches its prey vertically, darting down from above and sucking the prey into its long snout

truncate - having the end squared off

trunkfish - any fish species in the family Ostraciidae (order Tetraodontiformes). Trunkfishes are encased in an triangular inflexible bony carapace which protects them from predators.Only the jaw, eyes, the bases of the fins, and the caudal fin protrude from this carapace They are slow swimmers that move primarily by sculling with their dorsal and anal fins and use their caudal fin for sudden bursts of speed. They are also known as boxfishes or cowfishes

Image of tsunami damage

Tsunami damage at Seward, Alaska, following 1964 Good Friday Earthquake. (Photo: NOAA)


tsunami - a long-period gravity wave generated by a submarine earthquake or volcanic event

Image of starfish tube feet

The ventral side of a Pacific starfish shows its tube feet.


tube feet - extensions of the water-vascular system of echinoderms, protruding from the body and often ending in suckers. They may be used for locomotion and/or for maintaining a tight grip on prey or on the substrate

tube worm - a marine worm in the phylum Annelida, class Polychaeta, that lives within tubular cases made of mineral or chitinous secretions or of aggregated grit. Other worm-like invertebrates in the phyla Pogonophora and Phoronida have also been referred to as tubeworms

tubercle - any small, usually hard, knobby excrescence or lump. In pycnogonids and some cheliceramorph arthropods, the central eyes are carried on a tubercle

tubicolous - inhabiting a tube or tubular structure; tube dwelling, such as some marine polychaete worms

Image of trumpetfish snout

The trumpetfish has a snout which is tubiform or tubular in shape. (Photo: Copyright Digital Stock Corp.)


tubiform - a shape resembling a tube

tubules of Cuvier - eversible toxic or sticky tubules associated with the bases of the respiratory trees of some sea cucumbers (Holothuroidea-Echinodermata)

tubulin - the principal protein component of cellular microtubules (narrow, hollow tubes inside a cell), which are involved in cell division and cell movement

tumid - swollen, inflated.

tumor - a mass of new tissue, with no useful physiological function, growing independently of its surroundings

Image of orange tunicate

Orange colonial tunicate at Gray's Reef National Marine Sanctuary. Each of the individual tunicate's body is covered by the tunic. (Photo: NOAA)


tunic - the outer covering of a tunicate (Urochordata). The tunic is mostly composed of a protein and carbohydrates

turbidimeter - an instrument for measuring turbidity of liquids

turbidity - cloudy water, usually caused by the suspension of fine particles in the water column. The particles may be inorganic, such as silt, or organic, such as high densities of single-celled organisms

turbidity current - a current of rapidly moving, sediment-rich water moving down a submarine slope until it loses its energy. The current moves because it has a higher density and turbidity than the water through which it flows

turbinate - resembling an inverted cone

turquoise - blue green color

turriform - tower-shaped

tusk - an enlarged tooth

twilight - the time immediately before sunrise and after sunset when the sky remains illuminated

twilight zone - the term, "twilight zone" represents a transition from a region that receives sunlight during the daylight hours, to a region that remains in perpetual darkness. The coral-reef twilight zone is roughly defined as coral-reef habitat at depths between about 200 feet (60 meters) and 500 feet (150 meters). The upper limit represents the approximate maximum depth to which stony corals tend to dominate the reef structure, and the lower limit represents the maximum depth at which significant photosynthesis occurs (the maximum depth to which the living coral reef extends)

tympaniform - drum-shaped

type - in taxonomy, the standard of reference for determining the precise application of a name. Each taxon has, actually or potentially, a type: type of a nominal species is a specimen (type specimen or holotype); type of a nominal genus is the nominal species (type species); type of a nominal family is the nominal genus (type genus)

type collection - in taxonomy, a collection of type specimens

Type I error - the error of rejecting the null hypothesis when it is true

Type II error - the error of not rejecting the null hypothesis when it is false

type locality - in taxonomy, the geographical (and, where relevant, stratigraphical) location of the occurrence of the population from which the type specimen (i.e. holotype, lectotype or neotype) was taken

type material - in taxonomy, a collective term for all type specimens

type series - in taxonomy, the series of specimens which either constitutes the name-bearing type (syntypes) of a nominal species or subspecies or from which the name-bearing type has been or may be designated

type species - in taxonomy, the nominal species that is the name-bearing type of a nominal genus or subgenus

type specimen - in taxonomy, any specimen of the type series

typhoon - a hurricane that forms in the western Pacific Ocean

typological species - a species defined on the characters of the type specimen

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