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

Cavefish are cousins of the Mexican tetra river fish that flooded into underground caves over 100,000 years ago.

From Science Daily • Mar. 18, 2024

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 • Feb. 2, 2023

Another keystone species is the banded tetra, a fish in tropical streams, which supplies nearly all of the phosphorus, a necessary inorganic nutrient, to the rest of the community.

From Textbooks • Sep. 6, 2018

I will not only go to New York and hang out behind the counter and mess with people, but “The Original Soup Man” is now in supermarkets in tetra pack cartons.

From Washington Times • Jan. 11, 2017

The prefixes are: mono or proto, one; di or bi, two; tri or ter, three; tetra, four; pente, five; hex, six; etc.

From An Introduction to Chemical Science by Williams, Rufus Phillips