The answer to the crossword for the term WORD BEFORE SINE OR COSINE is ARC, which is a three-letter word. An ARC is a curved line that is part of a circle or other shape. In mathematics, sine and cosine are two of the most commonly used trigonometric functions. They are used to describe the relationship between angles and the lengths of the sides of a right triangle. The word before sine or cosine in this context is ARC, as it is the angle of the triangle that is being described.