1. a definite length of time marked off by two instants

Definition categories: time, amount, measure, quantity

2. a set containing all points (or all real numbers) between two given endpoints

Definition categories: thought, set

3. the distance between things

Similar word(s): separation

Definition categories: attribute, distance

4. the difference in pitch between two notes

Definition categories: communication

Sentences with interval as a noun:

- the interval between contractions during childbirth