Trig. [mod. f. CO>- pref. 4 + SINE. The L. cosinus occurs in Gunther, Canon Triangulorum (1620); F. cosine.] The sine of the complement of a given angle. (Abbrev. cos.)
1635. J. W[ells], Sciographia, 44. As the Radius, Is to the cosine of the angle given.
1726. trans. Gregory’s Astron., I. 141. The Co-sine of the Angle.
1880. Haughton, Phys. Geog., iii. 123. The mean annual evaporation … varies as the cosine of the latitude.
attrib. 1881. Nature, XXV. 167. Integrators were of three kinds: (1) radius machines, (2) cosine machines, (3) tangent machines.
