eight o'clock
noun1
The start of the ninth hour of the day; 8:00 a.m. (08:00).
In both the 12-hour clock and the 24-hour clock
- The breakfast buffet opens at eight o'clock (= "The breakfast buffet opens at 8:00 a.m.").
2
The start of the twenty-first hour of the day; 8:00 p.m. (20:00).
Only in the 12-hour clock
- Supper was served at eight o'clock (= "Supper was served at 8:00 p.m.").
3
Informal A position to the left and behind (horizontal clock orientation) (from the location of the 8 mark on a clock face)
- We've got a bogey at eight o'clock.