Tangent \Tan"gent\, n. [L. tangens, -entis, p. pr. of tangere to touch; akin to Gr. ? having seized: cf. F. tangente. Cf. Attain, Contaminate, Contingent, Entire, Tact, Taste, Tax, v. t.]

(Geom.) A tangent line curve, or surface; specifically, that portion of the straight line tangent to a curve that is between the point of tangency and a given line, the given line being, for example, the axis of abscissas, or a radius of a circle produced. See Trigonometrical function, under Function.

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 galvanometer (Elec.), a form of galvanometer having a circular coil and a short needle, in which the tangent of the angle of deflection of the needle is proportional to the strength of the current.

Tangent of an angle, the natural tangent of the arc subtending or measuring the angle.

Tangent of an arc, a right line, as ta, touching the arc of a circle at one extremity a, and terminated by a line ct, passing from the center through the other extremity o.

Source: Webster's Revised Unabridged Dictionary (1913)
 

Tangent \Tan"gent\, a. [L. tangens, -entis, p. pr.]

Touching; touching at a single point; specifically (Geom.) meeting a curve or surface at a point and having at that point the same direction as the curve or surface; -- said of a straight line, curve, or surface; as, a line tangent to a curve; a curve tangent to a surface; tangent surfaces.

Tangent plane (Geom.), a plane which touches a surface in a point or line.

Tangent scale (Gun.), a kind of breech sight for a cannon.

Tangent screw (Mach.), an endless screw; a worm.

Source: Webster's Revised Unabridged Dictionary (1913)