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# tetra

«tetra» in Mova's school dictionary: **a small, often brightly coloured freshwater fish from…** — its meaning for a pupil, its sense in the lessons and examples.

### part of speech

noun (a tetra, tetras); also a prefix tetra- meaning four

### meaning for a pupil

1) A tetra is a small, often brightly coloured freshwater fish from South America or Africa, popular in home aquariums, such as the neon tetra. [tree →](https://md.mova.elamur.ai/free/en/corpora/dictionaries/school/T/tetra/#m1)

2) Tetra- at the start of a word means four, as in tetrahedron (a solid with four faces) and tetrapod (an animal with four limbs). [tree →](https://md.mova.elamur.ai/free/en/corpora/dictionaries/school/T/tetra/#m2)

### sense in the lessons

In everyday life tetras are pet fish kept in tanks. In maths and science the prefix tetra- signals the number four. Phrases: neon tetra, a shoal of tetras, tetrahedron.

### examples

- We have six neon tetras in our fish tank. [tree →](https://md.mova.elamur.ai/free/en/corpora/dictionaries/school/T/tetra/#x1)
- Tetras like to swim together in a shoal. [tree →](https://md.mova.elamur.ai/free/en/corpora/dictionaries/school/T/tetra/#x2)
- A tetrahedron is a pyramid with four triangle faces. [tree →](https://md.mova.elamur.ai/free/en/corpora/dictionaries/school/T/tetra/#x3)
- The neon tetra has a shiny blue stripe. [tree →](https://md.mova.elamur.ai/free/en/corpora/dictionaries/school/T/tetra/#x4)
- Frogs, lizards, birds and people are all tetrapods. [tree →](https://md.mova.elamur.ai/free/en/corpora/dictionaries/school/T/tetra/#x5)
- Feed the tetras a small pinch of flakes. [tree →](https://md.mova.elamur.ai/free/en/corpora/dictionaries/school/T/tetra/#x6)
- The pet shop sells tetras, guppies and goldfish. [tree →](https://md.mova.elamur.ai/free/en/corpora/dictionaries/school/T/tetra/#x7)

### note

Countable: one tetra, two tetras. In maths, tetra- = 4 (tri- = 3, penta- = 5). Tetra Pak is a brand name for drink cartons, not a fish.

### Trees and pragmatics

[Every meaning and example of «tetra» parsed by Mova](https://md.mova.elamur.ai/free/en/corpora/dictionaries/school/T/tetra/), each sentence with its dependency tree and frames.