Definitions of tan:

• noun:   a light brown
• noun:   a browning of the skin resulting from exposure to the rays of the sun
• noun:   ratio of the opposite to the adjacent side of a right-angled triangle
• verb:   treat skins and hides with tannic acid so as to convert them into leather
• verb:   get a tan, from wind or sun
• adjective:   of a light yellowish-brown color
• name:  A surname (common: 1 in 20000 families; popularity rank in the U.S.: #2588)