The term TRIG TOPIC refers to topics related to trigonometry, which is a branch of mathematics that studies the relationships between angles and sides of triangles. The two crossword solutions for this term are SINE (4 letters) and ANGLE (5 letters). SINE is a trigonometric function that is used to calculate the ratio of the side opposite an ANGLE in a right triangle to the hypotenuse. ANGLE is a measure of the amount of turn between two lines or surfaces at a point.