Genre (from French genre 'kind, or sort') is any form or type of communication in any mode (written, spoken, digital, artistic, etc.) with socially-agreed-upon conventions developed over time. In popular usage, it normally describes a category of literature, music, or other forms of art or entertainment, whether written or spoken, audio or visual, based on some set of stylistic criteria, yet genres can be aesthetic, rhetorical, communicative, or functional. Genres form by conventions that change over time as cultures invent new genres and discontinue the use of old ones. Often, works fit into multiple genres by way of borrowing and recombining these conventions. Stand-alone texts, works, or pieces of communication may have individual styles, but genres are amalgams of these texts based on agreed-upon or socially inferred conventions. Some genres may have rigid, strictly adhered-to guidelines, while others may show great flexibility.

Genre began as an absolute classification system for ancient Greek literature, as set out in Aristotle's Poetics. For Aristotle, poetry (odes, epics, etc.), prose, and performance each had specific design features that supported appropriate content of each genre. Speech patterns for comedy would not be appropriate for tragedy, for example, and even actors were restricted to their genre under the assumption that a type of person could tell one type of story best.

Genres proliferate and develop beyond Aristotle’s classifications in response to changes in audiences and creators. Genre has become a dynamic tool to help the public make sense out of unpredictability through artistic expression. Given that art is often a response to a social state, in that people write, paint, sing, dance, and otherwise produce art about what they know about, the use of genre as a tool must be able to adapt to changing meanings.

Musician Ezra LaFleur argues that discussion of genre should draw from Ludwig Wittgenstein's idea of family resemblance. Genres are helpful labels for communicating but do not necessarily have a single attribute that is the essence of the genre.