Requisite is an adjective that means made necessary by particular circumstances or regulations. 

The Latin word requisitus (wreck we SUITE oose) meaning, ‘deemed necessary’ provides the basis for requisite. It shares its root with other English words like ‘require’ and ‘inquire.’ Example:

There I was, the last batter with two outs in the ninth inning and I was ready to hit a game-winning home run. The only problem was I forgot my requisite bat.