From Ancient Greek κοσμοπολίτης - "cosmopolitan, citizen of the world" ← κόσμος - "world" + πολίτης - "citizen".

Cosmopolitans are species of fish that are found on all continents.

A wide distribution of representatives of a species or larger taxon whose habitat covers vast areas of the Earth. Cosmopolitanism is opposed to endemism. Species or higher-ranking groups with cosmopolitan distribution are called cosmopolitans.

There are relatively few cosmopolitan species, mostly inhabitants of biotopes similar in different natural zones, such as marshes, ephemeral water bodies, oceanic pelagics. In particular, the killer whale (Orcinus orca), a marine predatory mammal, is cosmopolitan. Cosmopolitan species include the bivalve mussel edible mussel (Mytilus edulis), the diamondback stingray, the sea fox (Raja clavata). Typical cosmopolitans are protozoa.