marker

UK: /ˈmɑː^rkə^r/ US: /ˈmɑrkɚ/ ,(mär′kər)

WordReference Random House Learner's Dictionary of American English © 2025

mark•er /ˈmɑrkɚ/   n. [countable]

1. a thing that marks a place or shows the position of something:
   left a piece of paper in the book as a marker.
2. a tool for making marks:
   He used a yellow marker.

WordReference Random House Unabridged Dictionary of American English © 2025

mark•er  (mär′kər), n. 

1. a person or thing that marks.
2. something used as a mark or indication, as a bookmark or tombstone.
3. Games a person who records the scores, points, etc., as in a game or contest.
4. Games a counter used in card playing.
5. Genetics See genetic marker. 
6. Psychology an object, as a book or topcoat left at a library table, used to establish territorial possession in a public place.
7. Linguistics
   • an element of a construction, as a coordinating conjunction, that is not a part of either immediate constituent.
   • an element that indicates the grammatical class or function of a construction.
8. a small radio beacon, automatically operated, used for local navigation of vessels.
9. mile-marker.
10. Also called mark′er pen′, marking pen. a pen designed for making bold, colorful, or indelible marks, as in making signs or identifying objects.
11. Slang Terms, Games
    • a debt, esp. a gambling debt.
    • a written or signed promise to pay a debt, esp. a gambling debt;
      a promissory note or IOU.
12. Communications, Business Also called mark′er crude′. a grade of oil on which prices of other crude oils are based.
13. [CB Radio Slang.] one's location while driving on a highway, as determined by the nearest milepost.

• mark¹ + -er¹ 1480–90

Collins Concise English Dictionary © HarperCollins Publishers::

marker / ˈmɑːkə/ noun

1. something used for distinguishing or marking
2. (as modifier): a marker buoy
3. a person or thing that marks
4. a person or object that keeps or shows scores in a game
5. a trait, condition, gene, or substance that indicates the presence of, or a probable increased predisposition to, a physical or mental disorder
   See genetic marker