tetra

¹ American  

[te-truh] / ˈtɛ trə /

noun

1. any of several tropical, freshwater fishes of the family Characidae, often kept in aquariums.

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tetra- ² American  

1. a combining form meaning “four,” used in the formation of compound words.

   tetrabranchiate.

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tetra ¹ British  

/ ˈtɛtrə /

noun

1. any of various brightly coloured tropical freshwater fishes of the genus Hemigrammus and related genera: family Characidae (characins)

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tetra- ² British  

combining form

1. four

   tetrameter

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Usage

What does tetra- mean? Tetra- is a combining form used like a prefix meaning “four.” It is used in a great many scientific and other technical terms.In chemistry, tetra- is specifically used to indicate four atoms or four groups of atoms in compounds, e.g., tetrachloride.Tetra- ultimately comes from the Greek téttares, meaning “four.” The name of the classic video game Tetris is based in part on this Greek root. Find out the rest of the story of how Tetris got its name here.The Latin word for “four” is quattor, source of the combining forms quadr-, quadra-, quadri-, and quadru-. Learn about their specific applications in our Words That Use articles for the forms.What are variants of tetra-?When combined with words or word elements that begin with a vowel, tetra- becomes tetr-, as in tetracid.

Etymology

Origin of tetra¹

1930–35; shortening of New Latin Tetragonopterus former genus name. See tetragon, -o-, -pterous

Origin of tetra-²

< Greek, combining form of téttara, neuter of téttares four

Example Sentences

To study the evolution of smell-driven behaviours in a laboratory setting, the researchers chose two closely related fish of the Mexican tetra species -- the blind cave-dwelling subtype, and its sighted surface river-dwelling counterpart.

From Science Daily

When floods carried some Mexican tetra river fish, Astyanax mexicanus, into about 30 different caves, other fish of the same species remained at the surface, providing a natural study in contrasting evolutionary paths.

From Washington Post

But hunting in groups can enable predators to hunt prey that would otherwise be too fast, such as the tiny tetras.

From New York Times

Small fish, called tetras, are the target of the attack; they fly into the air and land stunned and motionless on the water.

From BBC

Similarly, Julia Giannini, a graduate student at Syracuse University in New York—who until recently worked with Puckett—reported a way to measure an effective “temperature” of a school of tetras.

From Science Magazine