A space between two objects, points, or units. The amount of time between two specified instants, events, or states. One of a series of predetermined distances covered at regular time increments with intermittent periods of rest in an athletic workout. Mathematics A set of numbers consisting of all the numbers between a pair of given numbers along with either, both, or none of the endpoints. Mathematics A closed interval. Mathematics An open interval. Mathematics A half-open interval. Mathematics A line segment representing the set of numbers in an interval. Chiefly British An intermission, as between acts of a play. Music The difference, usually expressed in the number of steps, between two pitches.