# Minute

The minute is a unit of time or angle. As a unit of time, the minute is most of times equal to 160 (the first sexagesimal fraction[1]) of an hour, or 60 seconds. In the UTC time standard, a minute on rare occasions has 61 seconds, a consequence of leap seconds (there is a provision to insert a negative leap second, which would result in a 59-second minute, but this has never happened in more than 40 years under this system). As a unit of angle, the minute of arc is equal to 160 of a degree, or 60 seconds (of arc). Although not an SI unit for either time or angle, the minute is accepted for use with SI units for both.[2] The SI symbols for minute or minutes are min for time measurement, and the prime symbol after a number, e.g. 5, for angle measurement. The prime is also sometimes used informally to denote minutes of time.

## History

In contrast to the hour, the minute (and the second) does not have a clear historical background. An early use of sexagesimal divisions of the hour is found in John of Sacrobosco's Computus (ca. 1235), where it was used in discussions of the length of the tropical year.[3] Another motivation that has been suggested for the emergence of these fine divisions of time was the construction of "precision" timepieces (mechanical and water clocks). However, no specific records of the origin for the division as 160 part of the hour (and the second 160 of the minute) have ever been found.

Historically, the word "minute" comes from the Latin pars minuta prima, meaning "first small part". This division of the hour can be further refined with a "second small part" (Latin: pars minuta secunda), and this is where the word "second" comes from. For even further refinement, the term "third" (160 of a second) remains in some languages, for example Polish (tercja) and Turkish (salise), although most modern usage subdivides seconds by using decimals. The symbol notation of the prime for minutes and double prime for seconds can be seen as indicating the first and second cut of the hour (similar to how the foot is the first cut of the yard or perhaps chain, with inches as the second cut). In 1267, the medieval scientist Roger Bacon, writing in Latin, defined the division of time between full moons as a number of hours, minutes, seconds, thirds, and fourths (horae, minuta, secunda, tertia, and quarta) after noon on specified calendar dates.[4]