Толковый словарь английского языка - tangent

I. adjective Etymology: Latin ~-, tangens, present participle of tangere to touch; perhaps akin to Old English thaccian to touch gently, stroke Date: 1594 1. meeting a curve or surface in a single point if a sufficiently small interval is considered , b. having a common ~ line at a point , having a common ~ plane at a point , diverging from an original purpose or course ; irrelevant , II. noun Etymology: New Latin ~-, tangens, from linea tangens ~ line Date: 1594 1. 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, 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 ~ of an angle of measure θ in radians, a line that is ~, an abrupt change of course ; digression , a small upright flat-ended metal pin at the inner end of a clavichord key that strikes the string to produce the tone