The twenty-fourth part of a day; sixty minutes.
- One of the 24 equal parts of a day.
- One of the points on a timepiece marking off 12 or 24 successive intervals of 60 minutes, from midnight to noon and noon to midnight or from midnight to midnight.
- The time of day indicated by a 12-hour clock.
- The time of day determined on a 24-hour basis: 1730 hours is 5:30 P.M.
- A unit of measure of longitude or right ascension, equal to 15° or 1/24 of a great circle.
- A customary or fixed time: the dinner hour.
- A set period of time for a specified activity: banking hours.
- A particular time: their hour of need.
- A significant time: Her hour had come.
- The present time: the man of the hour.
- The work that can be accomplished in an hour.
- The distance that can be traveled in an hour.
- A single session of a school day or class.
- A credit hour.
- Ecclesiastical The canonical hours.