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Important notice

Good news! We have updated our writing tools. Writing Tips and The Canadian Style have been combined to create a new tool called Writing Tips Plus.

Don’t forget to update your bookmarks. Within a few weeks, Writing Tips will no longer be available.

To begin your search, go to the alphabetical index below and click on the first letter of the word you are searching for.


O’clock is used with times on the hour, whether those times are written as words or in numbers (e.g. three o’clock or 3 o’clock, but not 4:30 o’clock).

  • Mischa said he would arrive about four o’clock in the morning.
  • When the Peace Tower bells rang at 10 o’clock, the veterans assembled for the parade.

Never use a.m. or p.m. with the expression o’clock.

  • Sarah called at 5 o’clock (not at 5 o’clock p.m.).