Overview

The term minute normally denotes a unit of time equal to sixty seconds. It is an everyday measure used for clocks, schedules and short intervals. The same word also names a small unit of angular measure equal to one sixtieth of a degree; in that sense it is called an arcminute.

Minute as a unit of time

As a time interval the minute equals 60 seconds and there are 60 minutes in an hour. The second is the SI base unit for time, defined by an atomic standard, so a minute is 60 SI seconds even though the minute itself is not an SI base unit. The common abbreviation for the time unit is min.

Minute as an angular measure

When used for angles, a minute (often called an arcminute) equals 1/60 of a degree. It is written using the prime symbol (′), for example 30′. A further subdivision, the arcsecond, is 1/60 of an arcminute and uses a double prime (″). Illustration: the Sun and Moon each subtend about 30 arcminutes as seen from Earth.

History and development

The division of hours and circles into sixtieths traces back to sexagesimal counting systems used in antiquity. Medieval and early modern scholars adopted subdivisions of degrees by analogy with hours, minutes and seconds of time. The widespread use of mechanical clocks after the 14th century made minutes a standard part of daily timekeeping; later, precision atomic clocks fixed the second and thereby the minute.

Uses and examples

  • Timekeeping and schedules: minutes are the principal unit for expressing short durations and clock time (minute).
  • Navigation and mapping: geographic coordinates are often given in degrees, minutes and seconds of arc.
  • Astronomy and optics: angular sizes, separations and telescope fields of view are commonly expressed in arcminutes and arcseconds.

Notable distinctions

Context determines meaning: "minute" in timetables refers to 60 seconds, while in charts or star catalogs it denotes 1/60 of a degree. Abbreviations differ too: min for time, and the prime symbol (′) for arcminutes. The minute of time remains a practical, non-SI unit built on the SI second, whereas the arcminute is an accepted subdivision of the degree in angular measurement.