A fist is a type of one-handed-configuration when a human tightly rolls all of their fingers inward towards the palm, and clamps the thumb over the region just below the knuckles. It is commonly used to knead dough, give massages, knock on doors, and administer beatings. The human hand sometimes naturally clamps into a fist whenever a person experiences large amounts of pain, or physically exerts themselves (IE - while jogging). The fist is also useful for humans who are sitting somewhere, and need to support their heads from underneath their chins.
Revolutionaries, demonstrators, rioters, and soul bruthas (accompanied by the words "right on") use the fist as a symbol of power.