Clade

Part of speech: noun

Pronunciation: /kleɪd/

Definitions

1. A classification of organisms that encompasses all descendants from a shared ancestor is used in evolutionary studies
2. In phylogenetics, this term denotes a grouping that includes a common ancestor along with all its descendants
3. A group of organisms considered to derive from a single common ancestor in biological classification

Etymology: Julian Huxley coined "clade" in 1957, in a paper titled "The Three Types of Evolutionary Process in Nature." He needed a word for a group of organisms descended from one common ancestor, and he reached back to Ancient Greek "kládos," meaning "shoot" or "branch." The image is of a single branch sprouting from a tree trunk, which is exactly how modern biologists draw the family tree of life. The word is a learned borrowing, meaning English took it directly from Greek through scholarly channels rather than through everyday speech. It is a doublet of "cladus," a Latin word of the same origin that already existed in English. Because the two words share a root but reached English by different routes, they are doublets, and the older form has a scholarly sense of its own. The term "clade" may also be related to "holt," an English word for a wood or grove, though that connection is uncertain.

Synonyms: group, lineage, branch, family, taxon