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"characteristic of monkeys or apes," c.1600, from Latin simia "ape," from simus "snub-nosed," from Greek simos "snub-nosed" (like the Scythians), also a masculine proper name, of unknown origin. Biological meaning "pertaining to monkeys" is from 1863. The noun meaning "an ape or monkey" first is attested in 1880.
Adjective Resembling or characteristic of apes or monkeys.
Noun An ape or monkey. Ther term simian is no longer used in scientific contexts. Compare prosimian.