tangent

American  

[tan-juhnt] / ˈtæn dʒənt /

adjective

1. in immediate physical contact; touching.

   Synonyms:

   meeting

2. Geometry.

   1. touching at a single point, as a tangent in relation to a curve or surface.

   2. in contact along a single line or element, as a plane with a cylinder.

3. tangential.

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noun

1. Geometry. a line or a plane that touches a curve or a surface at a point so that it is closer to the curve in the vicinity of the point than any other line or plane drawn through the point.

2. Trigonometry.

   1. (in a right triangle) the ratio of the side opposite a given angle to the side adjacent to the angle.

   2. Also called tan.  (of an angle) a trigonometric function equal to the ratio of the ordinate of the end point of the arc to the abscissa of this end point, the origin being at the center of the circle on which the arc lies and the initial point of the arc being on the x-axis. tg, tgn

   3. (originally) a straight line perpendicular to the radius of a circle at one end of an arc and extending from this point to the produced radius which cuts off the arc at its other end.

3. the upright metal blade, fastened on the inner end of a clavichord key, that rises and strikes the string when the outer end of the key is depressed.

idioms

1. off on / at a tangent, digressing suddenly from one course of action or thought and turning to another.

   The speaker flew off on a tangent.

tangent British  

/ ˈtændʒənt /

noun

1. a geometric line, curve, plane, or curved surface that touches another curve or surface at one point but does not intersect it

2.  tan.  (of an angle) a trigonometric function that in a right-angled triangle is the ratio of the length of the opposite side to that of the adjacent side; the ratio of sine to cosine

3. the straight part on a survey line between curves

4. music a part of the action of a clavichord consisting of a small piece of metal that strikes the string to produce a note

5. on a completely different or divergent course, esp of thought

   to go off at a tangent

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adjective

1. 1. of or involving a tangent

   2. touching at a single point

2. touching

3. almost irrelevant

tangent Scientific  

/ tăn′jənt /

1. A line, curve, or surface touching but not intersecting another.

2. The ratio of the length of the side opposite an acute angle in a right triangle to the side adjacent to the angle. The tangent of an angle is equal to the sine of the angle divided by the cosine of the angle.

3. The ratio of the ordinate to the abscissa of the endpoint of an arc of a unit circle centered at the origin of a Cartesian coordinate system, the arc being of length x and measured counterclockwise from the point (1, 0) if x is positive or clockwise if x is negative.

4. A function of a number x, equal to the tangent of an angle whose measure in radians is equal to x.

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tangent More Idioms  

1. see on a tangent.

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Other Word Forms

• quasi-tangent adjective
• tangency noun

Etymology

Origin of tangent

First recorded in 1585–90; from Latin tangent-, stem of tangēns “touching” (present participle of tangere “to touch”), in phrase līnea tangēns “touching line”

Explanation

A tangent is an entirely different topic or direction. When you want a break from geometry class, you might ask your teacher about his hobby of woodworking, a topic that's always good for a ten-minute tangent. Tangent is mainly a mathematical term, meaning a line or plane that intersects a curved surface at exactly one point. The non-mathematical meaning of tangent comes from this sense of barely touching something: when a conversation heads off on a tangent, it's hard to see how or why it came up. When talking about history, someone suddenly brings last night's basketball game? Definitely a tangent.

Example Sentences

At the same time, it was telling that a common reaction to Landry’s tangent was:

From The Wall Street Journal • Nov. 4, 2025

This is a bit of a tangent, but go with me for a second.

From Slate • Jun. 26, 2025

"Some of them will run straight, some of them will not start at all, some of them will go off on a tangent or bite each other," she explained.

From BBC • Apr. 19, 2025

Lakers coach JJ Redick went on a bit of a tangent last month about how an overly critical media might be partly responsible for a decline in NBA ratings this season.

From Los Angeles Times • Jan. 3, 2025

When you try to calculate the slope of a tangent line, zero wrecks your approximation process.

From "Zero: The Biography of a Dangerous Idea" by Charles Seife