The versine[2][3][4][5][6][7] or versed sine[8][1][9][10][11][4][12] is a trigonometric function already appearing in some of the earliest trigonometric tables. It is written as versin(θ),[4][9][10] sinver(θ),[13][14] vers(θ),[2][8][3][4][11][5][6] ver(θ)[15] or siv(θ).[16][17] In Latin, it is known as the sinus versus[16][17] (flipped sine), versinus, versus or the sagitta (arrow).[18]