minute of arc

A minute of arc, arcminute, or MOA is a unit of angular measurement, equal to one sixtieth (1/60) of one degree. Since one degree is defined as one three hundred sixtieth (1/360) of a circle, 1 MOA is 1/21600 of the amount of arc in a closed circle, or (π/10800) radians. It is used in those fields which require a unit for the expression of small angles, such as astronomy. The SI symbol for marking the arcminute is the prime (′) (U+2032), though a single quote (') (U+0027) is commonly used where only ASCII characters are permitted. One arcminute is written 1′ (or 1'). It is also abbreviated as arcmin or amin or, less commonly, the prime with a circumflex over it ().
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Noun
1. a unit of angular distance equal to a 60th of a degree
(synonym) minute, arcminute
(hypernym) angular unit
(part-holonym) degree, arcdegree
(part-meronym) second, arcsecond