touchdown

Short definition from Wiktionary

Noun

1. 1
   A six-point score occurring when the ball enters possession of a team's player in the opponent's end zone.
2. 2
   A defensive action of grounding the ball in the team's own in-goal to stop the play.
3. 3
   A try (scoring play of grounding the ball in the opposing team's in-goal).
4. 4
   The moment when an aircraft or spacecraft makes first or final contact with the ground during a landing.
5. 5
   The moment of contact of a tornado with the ground.