cosine

American  

[koh-sahyn] / ˈkoʊ saɪn /

noun

1. Trigonometry.

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

   2. the sine of the complement of a given angle or arc. cos

2. Mathematics. (of a real or complex numberx ) the function cos x defined by the infinite series 1 − (x 2 /2!) + (x 4 /4!) − + …, where ! denotes factorial. cos

---

cosine British  

/ ˈkəʊˌsaɪn /

noun

1.  cos.  a trigonometric function that in a right-angled triangle is the ratio of the length of the adjacent side to that of the hypotenuse; the sine of the complement

---

cosine Scientific  

/ kō′sīn′ /

1. The ratio of the length of the side adjacent to an acute angle of a right triangle to the length of the hypotenuse.

2. 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.

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

---

Etymology

Origin of cosine

1625–35; < New Latin cosinus. See co-, sine ( def. )

Example Sentences

You can also use the cosine similarity here to compare content you have already seen with other products.

From Scientific American • Aug. 17, 2023

These functions, such as the sine and cosine, are defined using right triangles.

From Scientific American • Apr. 10, 2023

The cosine of this angle is the length of the horizontal side divided by the hypotenuse.

From Scientific American • Apr. 10, 2023

We see that the cosine function is at the maximum displacement when and the sine function is at the equilibrium point when For example, consider the equation from Example 10.

From Textbooks • Dec. 1, 2021

The program took control of Parzival’s movements, synching them up with the music, and all four of my limbs were transformed into undulating cosine waves.

From "Ready Player One: A Novel" by Ernest Cline