B1 2K

O’clock

UK //əˈklɒk// US //əˈklɑːk// Pronunciation

Definition

A term used to indicate a specific hour.

Listen to definition

In simple words: Used to tell the time.

Examples

• The meeting starts at five o'clock.
• Let's meet at three o'clock.
• It’s exactly one o'clock now!

Usage notes

Use 'o'clock' to indicate whole hours. It's appropriate in both spoken and written English, but avoid in formal documents.

Grammar pattern

o'clock + time

Memory hint

Think of 'o' as the start of a circle, representing the full hour.

Collocations

• at five o'clock
• at two o'clock
• three o'clock sharp
• one o'clock in the afternoon

Synonyms

• hour
• time

Antonyms

• half past
• quarter past
• quarter to

Common mistakes

• Omitting 'o' in informal speech ('clock' instead of 'o'clock')
• Using 'o'clock' with minutes (e.g., 'two o'clock and fifteen')
• Confusing it with 'o' for informal time telling (e.g., 'It's 2 o').