A grouping of texts related within the system of literature by their sharing features of form and content. Ancient theoretical discussions of specific literary genres operate according to criteria which are one‐sidedly formal (generally metrical), thematic (the characters' moral or social quality, the general subject‐matter), or pragmatic (the situation of performance), but scarcely attempt to correlate or justify them.
Plato differentiates a number of existing poetic genres by their modes of presentation: mimetic (tragedy, comedy), narrational (dithyramb), or mixed (epic). But among the theoreticians it is only Aristotle who provides a genuinely complex theory, combining considerations of form, content, the author's and audience's psychology, metre, language, performance, traditionality, and evolution. Yet his surviving Poetics focuses mostly upon a single genre and is often elliptical and tentative: it furnishes many of the elements of a useful theory but does not fully work them out.