The minute is a unit of time equal to 1/60th of an hour or 60 seconds. Some rare minutes have 59 or 61 seconds; see leap second. The minute is not an SI unit, however it is accepted for use with SI units.
The symbol for minute or minutes is min.
The symbol for a minute of arc is a prime (′). For example, fifteen minutes could be written 15′. However, more commonly an apostrophe, or single quote (
U+0027), is used.
The symbol for a minute of right ascension is min. The Earth turns on its polar axis through fifteen minutes of arc in every minute of sidereal time. One minute of arc at the Earth's equator is approximately one nautical mile.
In old astronomical texts minute can also mean a unit of time equal to 1/60th of a day (24 usual minutes). These minutes correspond to the Latin diei scrupulis, and used to express periods of planetary motions. For example, Kepler in Harmonices Mundi gives Saturn year as 10759D12', that is 10759 (Earth) days, 4 hours, and 48 (usual) minutes.