clade definition by Webster's New World
Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio. Used by arrangement with John Wiley & Sons, Inc.
a group of living organisms that includes all the descendants sharing specific genetic traits of a common ancestor
clade definition by American Heritage Dictionary
The American Heritage® Dictionary of the English Language, 4th edition Copyright © 2010 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
A group of organisms, such as a species, whose members share homologous features derived from a common ancestor.
Origin: From Greek klados, branch.
clade - Science Definition
A grouping of organisms made on the basis of phylogenetic relationship, rather than purely on shared features. Clades consist of a common ancestor and all its descendants. The class Aves (birds) is a clade, whereas the class Reptilia (reptiles) is not, since it does not include birds, which are descended from the dinosaurs, a kind of reptile. Many modern taxonomists prefer to use clades in classification, and not all clades correspond to traditional groups like classes, orders, and phyla. Compare grade.