What do csc, cot, and sec stand for in math?

Does anyone know what they stand for and what they’re used for? All I know is that they relate to trigonometry in some way.

These are the reciprocal functions.

The cosecant is the reciprocal of the sine.

The cotangent is the reciprocal of the tangent.

The secant is the reciprocal of the cosine.

If you have sin x = 3/5, then csc x = 5/3

Csc math