four o'clock

• four-o'clock

four o'clock (uncountable)

1. (In both the 12-hour clock and the 24-hour clock) The start of the fifth hour of the day; 4:00 a.m. (04:00).

   The breakfast buffet opens at four o'clock (= "The breakfast buffet opens at 4:00 a.m.").

2. (Only in the 12-hour clock) The start of the seventeenth hour of the day; 4:00 p.m. (16:00).

   The next train comes at four o'clock (= "The next train comes at 16:00").

3. (informal) A position to the right and slightly behind (horizontal clock orientation) (from the location of the 4 mark on a clock face)

   We've got a bogey at four o'clock.

4. Any of several plants, of the genus Mirabilis, whose funnel-shaped flowers open in late afternoon.
5. The friarbirds (Philemon spp.); so called from its cry, which resembles these words.

• garden four o'clock (Mirabilis jalapa)
• Colorado four o'clock (Mirabilis multiflora)