Reverse Polish
Reverse Polish Notation is a mathematical notation, in which the operator follows the operands. The result is the removal of the need for parenthesis, because each operation only applies to a fixed number of values.
For example:
"3 4 +" is equal to 7, 3 + 4 using Infix notation.
"3 4 + 2 *" is equal to 14, (3+4)*2. Because the operator applies to only two values (in this case) before it, allowing the removal of parenthesis completely.