What does secant mean?
A secant is a line or line segment that intersects a curve at two or more points. It is especially important in circle geometry, where drawing a secant from an exterior point can help determine lengths, angles, and relationships involving chords and tangent lines. The related adjective describes an intersecting line, as in “secant line,” while the verb is a rare literary term meaning to cut across or divide by cutting. The central geometric distinction is that a secant passes through a curve, whereas a tangent touches it at one point without crossing it. Although the word may initially sound unusual, it names a precise and useful relationship that helps explain many standard theorems and constructions in elementary and advanced geometry.
A line or line segment that intersects a curve at two or more points, especially a circle.
"The secant passes through the circle and identifies two points on its circumference."
Standard mathematical terminology; “secant line” is the most common fixed expression.
Intersecting a curve at two or more points; constituting or forming a secant.
"Draw a secant line through the circle and mark its two points of intersection."
Used chiefly in geometric constructions, especially “secant line.”
To cut across or divide by cutting.
"The blade moved secantly across the surface."
Rare and literary in modern usage.
The standard plural of the mathematical noun.
"The secants intersect the circle at two points each."
A secant cuts through a curve; a tangent merely grazes it.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does secant come from?
The word comes through French sécante from Latin secantem, the present participle of secare, meaning “to cut.” Its geometric sense reflects a line that cuts across a curve rather than merely touching it. Related English words, including section, segment, sector, and bisect, share the same Latin root.
Related word forms
How secant is actually used
The noun is standard mathematical terminology. The adjective is common chiefly in the phrase “secant line.” The verb is rare and sounds formal or archaic in modern English.
Easily confused with secant
A tangent touches a curve at a single point without crossing it, whereas a secant intersects the curve at two or more points.
A segment is the portion of a line or curve between two endpoints, while a secant is defined by intersecting a curve at two or more points.