1. line or surface that touches another: a line, curve, or surface that touches another curve or surface but does not cross or intersect it
2. trigonometric function: for a given angle in a right-angled triangle, a trigonometric function equal to the length of the side opposite the angle divided by the length of the adjacent side
3. part of survey line: the part of a survey line that is straight
4. digression: a change of topic that is not relevant to the subject currently under consideration
5. music part of clavichord: a part of the clavichord that resembles a small hammer and strikes the strings
adjective
Definition:
1. mathematics Same as tangential (sense 2)
2. touching at one point: touching only at a single point
3. touching but not crossing: in contact, but not crossing or intersecting
4. away from point: not relevant to the subject currently under consideration
[Late 16th century. < Latin tangent-, present participle of tangere "touch"]
tan·gen·cy noun
go off at or on a tangent to change quickly and suddenly to a different subject or line of thought
Word History
The Latin word tangere "to touch," from which tangent is derived, is also the source of English attain, contact, intact, tact, tangible, and tax, and possibly also of taste.