A trigonometric function used in connection with right triangles; best seen as a ratio of side lengths.
In basic trigonometry, it is used to determine unknown side lengths or an acute angle measurement(s). In more advanced mathematics, cosine is treated simply as a function without an apparent or direct reference to a triangle (the triangle's presence becomes assumed). Examples of this may be seen in Calculus through the process of integration. Wherein, the function cosine may only be a part of a large equation.
Cosine is one component out of a three-part acronym known as: SOHCAHTOA. The term cosine occupies the "CAH," wherein the series forms: Cosine (equals) Adjacent (over) Hypotenuse.
Cosine thus represents the ratio of the Adjacent side length to the Hypotenuse side length -- this is all in relation to an (acute) angle, theta.
When dealing with an angle measurement, x ("theta"), the side "touching" the angle is referred to as the Adjacent side; the side furthest away from the angle is referred to as the Opposite side; and, in a right triangle, the hypotenuse always remains and, simplistically, may be recognized as the diagonal side.
In mathematical procedures, cosine is abbreviated as "cos" for convenience.
Note: UrbanDictionary entries do not support Entity, Hex or Decimal browser rendering. This definition replaces the Greek small letter, "theta", with an "x."
However, in reality, it appears as an "o" or a "zero" with a line going horizontally through the center.
In basic trigonometry, it is used to determine unknown side lengths or an acute angle measurement(s). In more advanced mathematics, cosine is treated simply as a function without an apparent or direct reference to a triangle (the triangle's presence becomes assumed). Examples of this may be seen in Calculus through the process of integration. Wherein, the function cosine may only be a part of a large equation.
Cosine is one component out of a three-part acronym known as: SOHCAHTOA. The term cosine occupies the "CAH," wherein the series forms: Cosine (equals) Adjacent (over) Hypotenuse.
Cosine thus represents the ratio of the Adjacent side length to the Hypotenuse side length -- this is all in relation to an (acute) angle, theta.
When dealing with an angle measurement, x ("theta"), the side "touching" the angle is referred to as the Adjacent side; the side furthest away from the angle is referred to as the Opposite side; and, in a right triangle, the hypotenuse always remains and, simplistically, may be recognized as the diagonal side.
In mathematical procedures, cosine is abbreviated as "cos" for convenience.
Note: UrbanDictionary entries do not support Entity, Hex or Decimal browser rendering. This definition replaces the Greek small letter, "theta", with an "x."
However, in reality, it appears as an "o" or a "zero" with a line going horizontally through the center.
by HB <3 SA August 29, 2008
Get the cosinemug. A function in mathematics
by jiexi December 8, 2003
Get the cosinemug. 
this word originates from this joke as it sounds like cousin
QWhat did one gangster mathmetician say to the other mathmetitian
A "sup cosine"
QWhat did one gangster mathmetician say to the other mathmetitian
A "sup cosine"
by Bill-Dizzle December 5, 2010
Get the Cosinemug. by KEMMA SLAY June 26, 2016
Get the I saw the cosinemug. by CEO Of Chicken Nuggies November 2, 2020
Get the Cosinemug. “Dude, are why the fuck do we even have LAW OF COSINES”
“idk bro but it's lowkey fun, here r the formulas”
Formulas FOR SIDES:
a² = b²+c²-2bc cosA
b²= a²+c²-2ac cos B
c²= a²+b²-2ab cos C
Formulas FOR SIDES: (always use cos-¹ to solve for angles)
cosA : b²+c²-a² / 2bc
cosB: a²+c²-b²/ 2ac
cosC: a² + b² / 2ab
“idk bro but it's lowkey fun, here r the formulas”
Formulas FOR SIDES:
a² = b²+c²-2bc cosA
b²= a²+c²-2ac cos B
c²= a²+b²-2ab cos C
Formulas FOR SIDES: (always use cos-¹ to solve for angles)
cosA : b²+c²-a² / 2bc
cosB: a²+c²-b²/ 2ac
cosC: a² + b² / 2ab
by kumicakes September 23, 2025
Get the Law of Cosinesmug.