Wiktionary
n. A competition held as part of a cycling stage race in which the riders are awarded points depending on how high they finish in each of the separate stages. The leader in the competition wears a special points jersey.
Wikipedia
The points classification is a secondary award category in road bicycle racing. Points are given for high finishes and, in some cases, for winning sprints at certain places along the route, most often called intermediate sprints. The points classification is the top prize for many cycling sprinters and is often known as the sprint classification; however, in some stage races these classifications are based on different criteria.
The points classification is arguably the second most important title and cycling jersey to win at a cycling stage race behind the general classification, which is the winner of the event by overall time.