ten o'clock

ten o'clock (uncountable)

(In both the 12-hour clock and the 24-hour clock) The start of the eleventh hour of the day; 10:00 a.m. (10:00).
The morning coffee break starts at ten o'clock (= "The morning coffee break starts at 10:00 a.m.").
(Only in the 12-hour clock) The start of the twenty-third hour of the day; 10:00 p.m. (22:00).
Supper service ends at ten o'clock (= "Supper service ends at 10:00 p.m.").
(informal) A position to the left and slightly ahead (horizontal clock orientation) (from the location of the 10 mark on a clock face)
We've got a bogey at ten o'clock.

the start of the eleventh hour

English