from The American Heritage® Dictionary of the English Language, 4th Edition
- n. Football An act of carrying, receiving, or gaining possession of the ball across the opponent's goal line for a score of six points.
- n. The contact, or moment of contact, of a landing aircraft or spacecraft with the landing surface.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A six-point score occurring when the ball enters possession of a team's player in the opponent's end zone. Analogous to a try in rugby.
- n. The moment when an aircraft makes first or final contact with the ground during a landing.
- n. A try
from the GNU version of the Collaborative International Dictionary of English
- n. The act of touching the football down behind the opponents' goal; also the score (6 points) resulting from such a play.
from The Century Dictionary and Cyclopedia
- n. In foot-ball, the touching of the ball to the ground by a player behind his opponent's goal; the play by which this is done.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- v. come or bring (a plane) to a landing
- n. a landing (as the wheels touch the landing field); especially of airplanes
- n. a score in American football; being in possession of the ball across the opponents' goal line
From the earlier practice of touching the ball to the ground behind the goal line.(American Heritage® Dictionary of the English Language, Fourth Edition)
touch + down. (Wiktionary)