Meme

Definition
A meme (pronounced meem) is a postulated unit of cultural ideas, symbols or practices, which can be transmitted from one mind to another through writing, speech, gestures, rituals or other imitable phenomena.

Overview
(The word is a blend of "gene" and the Greek word μιμητισμός (/mɪmetɪsmos/) for "something imitated".) Supporters of the concept regard memes as cultural analogues to genes, in that they self-replicate and respond to selective pressures.