n. The imitation or representation of aspects of the sensible world, especially human actions, in literature and art. (American Heritage Dictionary, 4th ed.)
Biology. The close external resemblance of an organism, the mimic, to some different organism, the model, such that the mimic benefits from the mistaken identity, as seeming to be unpalatable or harmful. (Dictionary.com)
More from Encyclopedia Britannica Online:
Basic theoretical principle in the creation of art. The word is Greek and means “imitation” (though in the sense of “re-presentation” rather than of “copying”). Plato and Aristotle spoke of mimesis as the re-presentation of nature. According to Plato, all artistic creation is a form of imitation: that which really exists (in the “world of ideas”) is a type created by God; the concrete things man perceives in his existence are shadowy representations of this ideal type. Therefore, the painter, the tragedian, and the musician are imitators of an imitation, twice removed from the truth. Aristotle, speaking of tragedy, stressed the point that it was an “imitation of an action”—that of a man falling from a higher to a lower estate. Shakespeare, in Hamlet’s speech to the actors, referred to the purpose of playing as being “…to hold, as ’twere, the mirror up to nature.” Thus, an artist, by skillfully selecting and presenting his material, may purposefully seek to “imitate” the action of life.
The place I recently spotted the word was in the book The Hand by Frank Wilson, which I will be posting about shortly. Wilson discusses Origins of the Modern Mind by Merlin Donald, and quotes this passage:
Mimetic skill or mimesis rests on the ability to produce conscious, self-initiated, representational acts that are intentional, but not linguistic…. Mimesis is fundamentally different from imitation and mimicry in that it involves invention of intentional representations….Mimetic skill results in the sharing of knowledge without every member of the group having to reinvent that knowledge….The primary form of mimetic expression was, and continues to be, visuomotor. The mimetic skills basic to child-rearing, toolmaking, cooperative gathering and hunting, the sharing of food and other resources, finding, constructing, and sharing shelter, and expressing social hierarchies and custom would have involved visuomotor behavior. (Donald, pp. 169-177, quoted in Wilson, p. 48)