The classical unities, Aristotelian unities, or three unities are rules for drama derived from a passage in Aristotle's Poetics. In their neoclassical form they are as follows:

1. unity of action: a play should have one action that it follows, with minimal subplots.
2. unity of time: the action in a play should occur over a period of no more than 24 hours.
3. unity of place: a play should exist in a single physical space and should not attempt to compress geography, nor should the stage represent more than one place.