meme

/meem/ , n. [coined by analogy with gene , by Richard Dawkins] An idea
considered as a replicator , esp. with the connotation that memes parasitize
people into propagating them much as viruses do. Used esp. in the phrase
meme complex denoting a group of mutually supporting memes that form an
organized belief system, such as a religion. This lexicon is an
(epidemiological) vector of the hacker subculture meme complex; each entry
might be considered a meme. However, meme is often misused to mean meme
complex. Use of the term connotes acceptance of the idea that in humans (and
presumably other tool- and language-using sophonts) cultural evolution by
selection of adaptive ideas has superseded biological evolution by selection
of hereditary traits.

Memes have featured extensively within popular culture, used both for
political satire and just plain amusement. The typical meme is a photo
together with one or two captions at the top and bottom in ALLCAPS letters.