A clade (from Ancient Greek κλάδος, klados, "branch") or monophylum (see monophyletic) is a group consisting of an ancestor and all its descendants, a single "branch" on the "tree of life". The ancestor may be an individual, a breeding pair, a population or even a species (extinct or extant). Many familiar groups, the rodents and the insects for example, are clades; others, like the lizards and the monkeys, are not.
Increasingly, taxonomists try to name preferably or only taxa that are clades.
The term was coined in 1958 by the biologist Julian Huxley.
Read more about Clade: Clades and Phylogenetic Trees, Terminology, Nomenclature and Taxonomy