hour

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. One of the 24 equal parts of a day.
2. n. 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.
3. n. The time of day indicated by a 12-hour clock.
4. n. The time of day determined on a 24-hour basis: 1730 hours is 5:30 P.M.
5. n. A unit of measure of longitude or right ascension, equal to 15° or ¹/₂₄ of a great circle.
6. n. A customary or fixed time: the dinner hour.
7. n. A set period of time for a specified activity: banking hours.
8. n. A particular time: their hour of need.
9. n. A significant time: Her hour had come.
10. n. The present time: the man of the hour.
11. n. The work that can be accomplished in an hour.
12. n. The distance that can be traveled in an hour.
13. n. A single session of a school day or class.
14. n. A credit hour.
15. n. Ecclesiastical The canonical hours.

Century Dictionary and Cyclopedia

1. n. A particular time; a fixed or appointed time; a set season: as, the hour of death.
2. n. The time marked or indicated by a timepiece; the particular time of day: as, what is the hour? at what hour shall we meet?
3. n. The twenty-fourth part of a civil day, or the twelfth part of a natural day or night. This division of time was invented by the Babylonians. Until modern times the hour was commonly considered as the twelfth part of the interval from sunrise to sunset or from sunset to sunrise. Until some time in the eighteenth century mean time was not used for ordinary purposes. Thus the Italians began the day half an hour after sunset, and reckoned 24 hours in each day. Until watches came into common use, in the seventeenth century, the time of day was determined ordinarily by the altitude of the sun, as in the following extract from Palladius, where the length of the shadow of a staff 4 feet long placed vertically determines the hours of the day reckoned from sunrise. Abbreviated h.
4. n. plural Set times of prayer; the canonical hours (which see, under canonical).
5. n. The offices or services prescribed for the canonical hours, or a book containing them. See book of hours, below.
6. n. In Greek myth, one of the Horæ or Hours, the goddesses of the seasons and guardians of the gates of heaven. They were held especially to personify the agreeable characteristics of the seasons, were closely associated with the Graces, and were attached to the train of Aphrodite. In art and poetry they were represented as young and graceful, decked with flowers and jewels.
7. n. The hour reckoned from sunrise as the beginning of the day.
8. n. In astronomy and geography, an angular measure of right ascension or longitude, being the twenty-fourth part of a great circle of the sphere, or fifteen degrees.
9. n. One hour in a shop. In many technical schools students are required to spend a certain number of hours in workshops. These are called shop-hours, to distinguish them from the hours spent in the recitation-room.

Wiktionary

1. n. A time period of sixty minutes; one twenty-fourth of a day.
2. n. A season, moment, time or stound.
3. n. poetic The time.
4. n. military, in the plural Used after a two-digit hour and a two-digit minute to indicate time.

GNU Webster's 1913

1. n. The twenty-fourth part of a day; sixty minutes.
2. n. The time of the day, as expressed in hours and minutes, and indicated by a timepiece; as, what is the hour? At what hour shall we meet?
3. n. Fixed or appointed time; conjuncture; a particular time or occasion
4. n. (R. C. Ch.) Certain prayers to be repeated at stated times of the day, as matins and vespers.
5. n. A measure of distance traveled.

WordNet 3.0

1. n. a period of time equal to 1/24th of a day
2. n. distance measured by the time taken to cover it
3. n. a special and memorable period
4. n. clock time