From The Collaborative International Dictionary of English v.0.48 :
Cebidae \Cebidae\ prop. n.
A natural family including all the New World monkeys except
marmosets and tamarins.
Syn: family Cebidae.
[WordNet 1.5]
From WordNet (r) 3.0 (2006) :
Cebidae
n 1: all the New World monkeys except marmosets and tamarins
[syn: Cebidae, family Cebidae]