bottom of the hour
Definition from Wiktionary, the free dictionary
- The time at (or very close to) half the next hour of time. Refers to the time when the position of the long hand is pointing toward the number 6, or exactly halfway between the preceding hour and the upcoming one.
- "At Seven o'clock, He said to get in touch with him again at the 'bottom of the hour,' so I called him back at seven thirty."