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. It is used in those fields which require a unit for the expression of small angles, such as astronomy or marksmanship. Symbols, abbreviations and subdivisions The standard symbol for marking the arcminute is the prime (′) (U+2032), though a s… (More on Arcsecond)