A beret is a “round flattish cap made of felt or cloth…worn by local peasants.”
So from peasant’s headgear, the humble beret has become the normal, day-to-day wear of the American Soldier. The black color was authorized to be worn by all US Army soldiers just recently (November 2001); previously it was only authorized for Army Rangers. Although there were pre-formed berets available for purchase, we at the chaplain school were taught how to prepare the beret the old fashioned way.
The black (not pre-formed) US Army beret usually comes from the clothing store stiff. So that it can be formed properly, the owner has to first (1) shave it until it’s thin or pliable enough to “hug” the head of the wearer; (2) after shaving, the beret has to be soaked in lukewarm water until completely wet; (3) after soaking, the beret is squeezed (not wrung) of excess water, then (4) shaped on the wearer’s head and left there until completely dry. Doing this will form the beret according to the contour of the wearer’s head.