 Conversely, the term "polyphyly", or "polyphyletic", builds on the ancient greek prefix (), meaning "many, a lot of", and refers to the fact that a polyphyletic group includes organisms arising from "multiple" ancestral sources.By comparison, the term "paraphyly", or "paraphyletic", uses the ancient greek prefix (), meaning "beside, near", and refers to the situation in which one or several monophyletic subgroups are "left apart" from all other descendants of a unique common ancestor.That is, a paraphyletic group is "nearly" monophyletic, hence the prefix "".