Arcsecond

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 ().
See more at Wikipedia.org...

Noun
1. a 60th part of a minute of arc; "the treasure is 2 minutes and 45 seconds south of here"
(synonym) second
(hypernym) angular unit
(part-holonym) minute, arcminute, minute of arc

An angular measurement which corresponds to one three hundred and sixtieth of a degree. See also arcminute .