interval noun

ADJ. brief, short She ruled for ten years, except for a brief interval. | long, wide You are advised to leave a wide interval before you have your next child. | decent

PREP. at ~s At intervals a bell rings and workers stop for a drink. | ~ between The intervals between his various illnesses grew shorter and shorter.

PHRASES at fixed/frequent/periodic/regular intervals Trains run at fixed intervals. He returned home during the day at regular intervals. | at hourly/weekly/fortnightly/monthly, etc. intervals Meetings are held at monthly intervals.