/ ˈmɑːkə(r); NAmE ˈmɑːrk-/ noun
1.
[ C ] an object or a sign that shows the position of sth :
a boundary marker
He placed a marker where the ball had landed.
2.
[ sing. ] a ~ (of / for sth) a sign that sth exists or that shows what it is like :
Price is not always an accurate marker of quality.
3.
( BrE also ˈmarker pen ) a pen with a thick felt tip
4.
( BrE ) ( NAmE grader ) a person who marks / grades students' work or exam papers
5.
( BrE ) ( in team games, especially football ( soccer ) ) a player who stays close to a player on the other team in order to stop them getting the ball