■ noun
1》 an object used to indicate a position, place, or route.
↘a distinctive feature or characteristic indicative of a particular quality or condition.
↘ Genetics an allele used to identify a chromosome or to locate other genes on a genetic map.
2》 a felt-tip pen with a broad tip.
3》 Brit. (in team games) a player who marks an opponent.
4》 a person who marks a test or examination.
↘a person who records the score in a game, especially in snooker or billiards.
5》 N. Amer. informal a promissory note; an IOU.