## Hour |

An **hour** (**h**;^{[1]} also abbreviated **hr**.) is a ^{1}⁄_{24} of a

The hour was initially established in the ^{1}⁄_{12} of the **seasonal**, **temporal**, or **unequal hours** varied by **Equal** or **equinoctial hours** were taken as ^{1}⁄_{24} of the day as measured from noon to noon; the minor seasonal variations of this unit were eventually smoothed by making it ^{1}⁄_{24} of the

In the modern ^{[a]} making it last 3,599 or 3,601 seconds, in order to keep it within 0.9 seconds of

*Hour* is a development of the * houre* and

It displaced **tide** tīd, "time"^{[4]} and **stound** stund, *span of time*.^{[5]} The Anglo-Norman term was a * ure*, a variant of

Like Old English * tīd* and

The **time of day** is typically expressed in English in terms of hours. Whole hours on a *o'clock*, from the older *of clock*.^{[6]} (10 am and 10 pm are both read as "ten o'clock".)

Hours on a ^{[7]} (1000 is read "ten hundred" or "ten hundred hours"; 10 pm would be "twenty-two hundred".)

Fifteen and thirty minutes past the hour is expressed as "a quarter past" or "after"^{[8]} and "half past", respectively, from their fraction of the hour. Fifteen minutes before the hour may be expressed as "a quarter to", "of", "till", or "before" the hour.^{[8]} (9:45 may be read "nine forty-five" or "a quarter till ten".)