Glossary of Literary Theory by Greig E. Henderson and Christopher Brown

Nature:

A term used by classical, Renaissance, and neoclassical writers (Horace, Sir Philip Sidney, John Dryden, and others) to describe what art should seek to imitate and to represent realistically -- namely, the external world and the action and life of human beings within it. (See also Art, Decorum, Delight, Instruction.)