Tangent

n. [Fr. tangente (sc. ligne), from tangent, Lat. tangens, p. pr. of tangere, to touch; It. & Sp. tangente.] (Geom.) A right line which touches a curve, but which, when produced, does not cut it;—applied also to a curve, or to a plane or curved surface, which touches another at a single point.

Artificial or logarithmic tangent, the logarithm of the natural tangent of an arc.—Natural tangent, a decimal expressing the length of the tangent of an arc, the radius being reckoned unity.—Tangent of an arc (Trig.), a right line, as t a, touching the arc at one extremity a, and terminated by a secant c t, passing through the other extremity o.—Tangent-scale (Gun.), an implement used in pointing cannon.

c, c, c, Tangents.

a o, arc; a t, tangent; t c, tangential radius.