What is the meaning of Tetra?

Any of numerous species of small freshwater fish of the South American family Characidae and West African family Alestidae, popular in home aquariums.

Tetra Pak (type of container)

tetra (fish of the family Characidae, commonly kept as aquarium fish)

feminine singular of tetro

tetra ((fish))

inflection of tēter:

1. nominative/vocative feminine singular
2. nominative/accusative/vocative neuter plural

nominative/vocative feminine singular

nominative/accusative/vocative neuter plural

ablative feminine singular of tēter

terry (fabric)

clipping of tetrachlorometan

tetra (fish)

Source: wiktionary.org