"A meme (/?mi?m/ MEEM) is an idea, behavior, or style that spreads from person to person within a culture.[1] A meme acts as a unit for carrying cultural ideas, symbols, or practices that can be transmitted from one mind to another through writing, speech, gestures, rituals, or other imitable phenomena with a mimicked theme. Supporters of the concept regard memes as cultural analogues to genes in that they self-replicate, mutate, and respond to selective pressures.[2]"

-Wikipedia