Merriam-Webster's Collegiate® Dictionary, 11th Edition
HAT
I. noun see: hood Date: before 12th century a covering for the head usually having a shaped crown and brim,
2. a distinctive head covering worn as a symbol of office, an office, position, or role assumed by or as if by the wearing of a special hat , hatless adjective
II. verb (hatted; hatting)
Date: 15th century
transitive verb to furnish or provide with a hat, intransitive verb to make or supply hats