Merriam-Webster's Collegiate® Dictionary, 11th Edition
TEE
I. noun
Etymology: Middle English
Date: 15th century
the letter t , something shaped like a capital T, a mark aimed at in various games (as curling),
II. noun
Etymology: origin unknown
Date: 1673
1. a small mound or a peg on which a golf ball is placed before being struck at the beginning of play on a hole, a device for holding a football in position for kicking, an adjustable post on which a ball is placed for batting (as in T-ball), the area from which a golf ball is struck at the beginning of play on a hole,
III. transitive verb (teed; teeing)
Date: 1673
to place (a ball) on a tee