(medicine) The first sixty minutes after sustaining major traumatic injury, during which there is the highest likelihood that prompt medical treatment will prevent death.

The time in the middle of the day when one stops one's activities (working, studying, etc) to have lunch.

(astronomy, physics) A unit of length equal to the distance light travels in one hour

plural of bottom of the hour

plural of top of the hour

plural of hour circle

(astronomy) The great circle through an object whose location is to be determined and the two celestial poles.

(Scotland) A time of trial or difficulty.

Suffix used to indicate the age of something or someone, in terms of hours.

plural of hour glass