Definition of "cosine" []

• In a right triangle, the ratio of the length of the side adjacent to an acute angle to the length of the hypotenuse. (noun)
• The abscissa at 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. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Measuring Relational Similarity with VSM  The measure of similrity of R1 and R2 is given by the cosine of the angle Ɵ between r1 and r2: cosine  = ∑ r1, i. r2, i = r1. r2 = r1. r2"
• "So, if the current is sinusoidal, you know the derivative of a sine to be a cosine, which is 90° out of phase."
• "Did you know that it's possible to calculate a cosine even if you think "cosine" is a brand of nasal decongestant?"