A

**second of arc**or

**arcsecond**is a unit of angular measurement which comprises one-sixtieth of an arcminute, or, put another way, 1/3600 of a degree of arc. The symbol for one arcsecond is 1".

It can be abbreviated as **arcsec**, but should then not be confused with the inverse trigonometric function arc secant, which has the same abbreviation\n