'ani' originates from a South American indigenous language (recorded in early naturalists' accounts), specifically the word 'ani', where it was the local name for the bird.

'ani' entered scientific Latin usage as the species name in the binomial 'Crotophaga ani' and was adopted into English ornithological usage; the plural 'anis' follows regular English pluralization.

Initially it meant the local name for this bird, and over time it kept that sense as the English name for the species (and its plural).