1. any of several tropical American birds of the genus Procnias having a bell-like call
The Collaborative International Dictionary of English v.0.48:
Bellbird \Bell"bird`\, n. [So called from their notes.] (Zool.)
(a) A South and Central American bird of the genus
Casmarhincos, and family Cotingid[ae], of several
species; the campanero.
(b) The Myzantha melanophrys of Australia.
[1913 Webster] bell-bottomed
WordNet (r) 3.0 (2006):
n 1: any of several tropical American birds of the genus
Procnias having a bell-like call