From wikipedia,
In more specific terms, a meme is a self-propagating unit of cultural evolution having some resemblance to the gene (the unit of genetics). The difference lies in the replicative potential and minimally required resources to replicate. Memes can represent parts of ideas, languages, elemental particles, tunes, designs, skills, moral and aesthetic values and anything else that is commonly learned and passed on to others as a unit. The study of evolutionary models of information transfer is called memetics.
In casual use, the term meme is sometimes used to mean any piece of information that is passed from one mind to another. This is much closer to the analogy of “language as a virus” than it is to Dawkins’s analogy of memes as replicating behaviors.
