Dawkins coined the word meme (the behavioural equivalent of a gene) as a way to encourage readers to think about how Darwinian principles might be extended beyond the realm of genes. Indeed, it was intended as an extension of his "replicators" argument, but it took on a life of its own in the hands of other authors such as Daniel Dennett and Susan Blackmore. These popularisations then led to the emergence of memetics, a field from which Dawkins has distanced himself.
Dawkins's meme refers to any cultural entity that an observer might consider a replicator of a certain idea or complex of ideas. He hypothesised that people could view many cultural entities as capable of such replication, generally through exposure to humans, who have evolved as efficient (although not perfect) copiers of information and behaviour. Because memes are not always copied perfectly, they might become refined, combined, or otherwise modified with other ideas; this results in new memes, which may themselves prove more or less efficient replicators than their predecessors, thus providing a framework for a hypothesis of cultural evolution based on memes, a notion that is analogous to the theory of biological evolution based on genes.
Although Dawkins invented the specific term meme independently, he has not claimed that the idea itself was entirely novel, and there have been other expressions for similar ideas in the past. For instance, John Laurent has suggested that the term may have derived from the work of the little-known German biologist Richard Semon. In 1904, Semon published Die Mneme (which appeared in English in 1924 as The Mneme). This book discusses the cultural transmission of experiences, with insights parallel to those of Dawkins. Laurent also found the term mneme used in Maurice Maeterlinck's The Life of the White Ant (1926), and has highlighted the similarities to Dawkins's concept. Author James Gleick describes Dawkins's concept of the meme as "his most famous memorable invention, far more influential than his selfish genes or his later proselytizing against religiosity".