cal·li·thrix I. \ˈkaləˌthriks\noun Usage: capitalized Etymology: New Latin, from Latin, an ape, from Greek kallithrix beautiful-haired, from kalli- calli- + thrix hair : a genus consisting of the true marmosets II. Etymology: New Latin, from Latin, an ape synonym of callicebus — a prior name invalid as a homonym of 1Callithrix