Definition of beanies:
(n) :
(clothing) A cap that fits the head closely, usually knitted from wool.
(n) :
A head-hugging brimless cap, with or without a visor, made from triangular sections of cloth, leather, or silk joined by a button at the crown and seamed together around the sides.
(n) :
(informal) A Beanie Baby, a small soft toy filled with beans or similar stuffing.