trop·ic·bird (tr?p??k-bûrd?)n. Any of several predominantly white, swift-flying seabirds of the genus Phaethon of warm regions, having a pair of very long central tail feathers.American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.tropicbird (?tr?p?k?b??d) n (Animals) any aquatic bird of the tropical family Phaethontidae, having long slender tail feathers and a white plumage with black markings: order Pelecaniformes (pelicans, cormorants, etc)[C17: so called because it is found in the tropical regions]Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014