It's an acronym for the order of operations you perform while doing algebraic equations

Parenthesis (the highest priority, you always do these first)

Exponents

Multiply/Divide

Addition/Subtraction (the lowest priority, do these last)

Parenthesis (the highest priority, you always do these first)

Exponents

Multiply/Divide

Addition/Subtraction (the lowest priority, do these last)