Learner's definition of TOUCHDOWN
1 [count], American football : a score that is made by carrying the ball over the opponent's goal line or by catching the ball while standing in the end zone
◊ A touchdown is worth six points and is usually followed by a kick that is worth another point.
2 [count], rugby : the act of scoring points by putting the ball on the ground behind an opponent's goal line 3 [count, noncount] : the moment when an airplane or spacecraft touches the ground at the end of a flight
— see also touch down at 1touch