hour

1. a period of time equal to a twenty-fourth part of a day and night and divided into 60 minutes.

   an extra hour of daylight in the winter evenings

   rates of pay were low, starting at £3.20 an hour

   a two-hour operation

2. a time of day specified as an exact number of hours from midnight or midday.

   the clock in the sitting room struck the hour

3. a fixed period of time for an activity, such as work, use of a building, etc.

   the dinner hour

   licensing hours

   opening hours

4. (in the Western (Latin) Church) a short service of psalms and prayers to be said at a particular time of day, especially in religious communities.

   an organized life of prayer including the canonical hours

5. 15° of longitude or right ascension (one twenty-fourth part of a circle).

Middle English: from Anglo-Norman French ure, via Latin from Greek hōra ‘season, hour’.