Someone or something that creates marks, such as a felt-tipped pen, a scorekeeper for billiards, or a device used in paintball.

A person or thing used to mark a position or amount, such as an objective, a record of debt, a grammatical function indicator, a gene or dna sequence used for identification, a diagnostic indicator, a military soldier, a sewing machine attachment, a counter, or various objects used to mark a place on the landscape.

(UK) Someone who assigns marks on tests, examinations, etc.; a grader.

(colloquial) The ink marks or residue of a felt-tipped pen.

(figurative) A personal favor owed to someone, whether written or not.

(competition law) A formal certification that a company was the first to approach a competition authority to reveal the existence of a cartel, generally entitling it to greater leniency during the cartel's dissolution and punishment.

(sports) A player on defense used to mark one or more offensive players.

(Philippines, informal, basketball, volleyball) A point, unit of scoring in a game or competition.

To mark or write on (something) using a marker