(in a right triangle) the ratio of the side adjacent to a given angle to the hypotenuse.
the sine of the complement of a given angle or arc. Abbreviation: cos
Mathematics. (of a real or complex number x ) the function cos x defined by the infinite series 1 − ( x2 /2!) + ( x4 /4!) − + …, where ! denotes factorial. Abbreviation: cos Compare sine( def 3 ), factorial( def 1 ).
Origin: 1625–35; < Neo-Latincosinus. See co-, sine1
The abscissa of the endpoint of an arc of a unit circle centered at the origin of a Cartesian coordinate system, the arc being of length x and measured counterclockwise from the point (1, 0) if x is positive or clockwise if x is negative.
A function of a number x, equal to the cosine of an angle whose measure in radians is equal to x.