cosine
Mathematical term for the trigonometric function cosine. Used in geometry and analysis.
Find the side length of the triangle using the law of cosines.
この関数のグラフは余弦曲線を描く。
The graph of this function draws a cosine curve.
direction cosine
From 余 (complement) + 弦 (chord, bowstring), referring to the complementary relationship with sine in a right triangle. The exact historical derivation is uncertain, but the term is a standard Sino-Japanese mathematical coinage.