parenthesis - technical definition

The left parenthesis "(" and right parenthesis ")" are used to delineate one expression from another. For example, in the query list for size="34" and (color = "red" or color ="green"), parentheses group the ORs together so they are a distinct entity from the AND.

In programming, parentheses are used to surround input parameters of a function call. For example, in C, the string compare statement strnicmp (itemA, itemB, 10) uses parentheses to group the ITEMA, ITEMB and 10 values handed over to the function.