Pre-Calculus is a course of mathematics that is typically taken in high school or college. It is a prerequisite for Calculus and focuses on topics such as algebra, trigonometry, and analytic geometry. The term PRE-CALC can be broken down into two parts: PRE and CALC. PRE stands for pre-calculus and CALC stands for calculus. Trigonometry is an important part of pre-calculus and can be abbreviated to TRIG, which is a four letter word.