1 An intervening time.
1.1 A component of activity in interval training.
2 A pause or break in activity.
2.1 British A period of time separating parts of a theatrical or musical performance.
2.2 A break between the parts of a sports match.
3 A space between two things; a gap.
4 The difference in pitch between two sounds.
Middle English from Old French entrevalle, based on Latin intervallum ‘space between ramparts, interval’, from inter- ‘between’ + vallum ‘rampart’.
It is with some satisfaction that WotD has progressed through many words with mostly no interrupting intervals.