Noun | 1. | ![]() New World monkey, platyrrhine, platyrrhinian - hairy-faced arboreal monkeys having widely separated nostrils and long usually prehensile tails Callithricidae, family Callithricidae - marmosets true marmoset - a marmoset Cebuella pygmaea, pygmy marmoset - the smallest monkey; of tropical forests of the Amazon leoncita, lion marmoset, lion monkey, tamarin - small South American marmoset with silky fur and long nonprehensile tail |