What are sine cosine tangent cosecant secant cotangent?

They are usually introduced in mathematics as trigonometric ratiOS.

In a right angled triangle, there is (by definition) a right angle and the side opposite that is called the hypotenuse. Select one of the two acute angles, X. It is formed by two sides, one of which is the hypotenuse and the other is called the adjacent side. The third side, opposite the selected angle, is called the opposite side.

Suppose the lengths of these three sides are h, a and o. Then

sin(X) = o/h cosec(X) = 1/sin(X) = h/o

cos(X) = a/h sec(X) = 1/cos(X) = h/a

tan(X) = o/a cot(X) = 1/tan(X) = a/o