mark ‧ er /ˈmɑːkə $ ˈmɑːrkər/ BrE AmE noun [countable]
1 . an object, sign etc that shows the position of something:
He buried the bodies in a single grave with a wooden cross as a marker.
2 . something which shows that a quality or feature exists or is present SYN mark
marker of/for
antibodies which are a marker of hepatitis
the use of slang as a marker of social identity
3 . ( also marker pen British English ) a large pen with a thick point made of ↑ felt , used for marking or drawing things ⇨ ↑ Magic Marker
4 . put/lay/set down a marker British English to say or do something that clearly shows what you will do in the future