Noun
apomorphy (plural apomorphies)
(systematics) A derived characteristic of a clade. Any feature novel to a species and its descendants.
An alternate definition was provided in 2001, naming Carinatae an apomorphy -based clade defined by the presence of a keeled sternum. Source: Internet
"It is now thought that the possession of two cotyledons is an ancestral feature for the taxa of the flowering plants and not an apomorphy for any group within. Source: Internet
The terms plesiomorphy and apomorphy are relative; their application depends on the position of a group within a tree. Source: Internet