tangent

I. adjective Etymology: Latin tangent-, tangens, present participle of tangere to touch; perhaps akin to Old English thaccian to touch gently, stroke Date: 1594 1. a. meeting a curve or surface in a single point if a sufficiently small interval is considered <

straight line tangent to a curve

> b. (1) having a common tangent line at a point <

tangent curves

> (2) having a common tangent plane at a point <

tangent surfaces

> 2. diverging from an original purpose or course ; irrelevant <

tangent remarks

> II. noun Etymology: New Latin tangent-, tangens, from linea tangens tangent line Date: 1594 1. a. the trigonometric function that for an acute angle is the ratio between the leg opposite to the angle when it is considered part of a right triangle and the leg adjacent b. a trigonometric function that is equal to the sine divided by the cosine for all real numbers θ for which the cosine is not equal to zero and is exactly equal to the tangent of an angle of measure θ in radians 2. a line that is tangent; specifically a straight line that is the limiting position of a secant of a curve through a fixed point and a variable point on the curve as the variable point approaches the fixed point 3. an abrupt change of course ; digression <

the speaker went off on a tangent

> 4. a small upright flat-ended metal pin at the inner end of a clavichord key that strikes the string to produce the tone