Longman Dictionary of Contemporary English
Wiktionary
n. 1 (context soccer English) A form of direct free kick, taken from the penalty spot after a defensive foul in the penalty box, with only the goalkeeper defending the goal, 2 (context rugby English) A form of free kick in which the ball may be kicked towards touch, towards the goal or dribbled
Wikipedia
A penalty kick (often abbreviated to penalty) is a method of restarting play in association football, taken from 11 meters (approximately 12 yards) out from the goal, on the penalty mark.
Penalty kicks are performed during normal play. They are awarded when a foul that is punishable by a direct free kick is committed within the offending player's own penalty area. Similar kicks are made in a penalty shootout in some tournaments to determine which team is victorious after a drawn match; these are governed by slightly different rules.
In practice, penalties are converted to goals more often than not, even against world class goalkeepers. This means that penalty awards are often decisive, especially in low-scoring games. Missed penalty kicks are often demoralising to players because it is an easy opportunity to score.
Usage examples of "penalty kick".
His head rolled and he relaxed and slumped across the floor at full length, as if he were diving for a penalty kick.
The penalty kick that one of the lads aimed at my jaw knocked me backwards into the ditch.