marker

noun

mark·​er ˈmär-kər 

1

: one that marks

2

: something used for marking: such as

a

: a type of felt tip pen that makes wide lines

drew a tree with green and brown markers

used a permanent marker to label the boxes

b

: any of various sewing devices for making or indicating guidelines

a pin marker for hemlines

3

: score sense 7

specifically : run

4

: promissory note, iou

5

: something that serves to identify, predict, or characterize: such as

a

: biomarker

b

: genetic marker

Synonyms of marker

• label

Examples of marker in a Sentence

A person's accent can be a marker of social class.

the markers on the rock and mineral specimens were old and faded

Recent Examples on the Web

The American Society for Reproductive Medicine has stated that ovarian reserve markers shouldn’t be used as a fertility test for women who aren’t infertile or whose fertility hasn’t been evaluated. —Allison Palmer, Miami Herald, 6 Apr. 2026

The American Society for Reproductive Medicine has stated that ovarian reserve markers shouldn’t serve as a fertility test for women who aren’t infertile or whose fertility hasn’t been evaluated. —Allison Palmer, Sacbee.com, 6 Apr. 2026

Evidence markers are also placed in the parking lot of a marijuana dispensary at the corner of Broadway and Maple. —Logan Smith, CBS News, 5 Apr. 2026

A number of over-the-counter tests use these markers to estimate biological age. —Lindsey Leake, NBC news, 5 Apr. 2026

Word History

First Known Use

15th century, in the meaning defined at sense 1

Phrases Containing marker

• genetic marker

Rhymes for marker

• barker
• darker
• starker
• biomarker

Kids Definition

marker

noun

mark·​er ˈmär-kər 

1

: one that marks

2

: something used for marking

Medical Definition

marker

noun

mark·​er ˈmär-kər 

: something that serves to identify, predict, or characterize

a surface marker on a cell that acts as an antigen

: as

a

: biomarker

The recent discovery of a serological marker for the hepatitis C virus has greatly improved diagnostic accuracy for this form of hepatitis.

—Gary P. Wormser, letter in The Journal of the American Medical Association

b

: genetic marker

The idea in genetic linkage analysis is to see if any particular marker, which serves as a signpost for a specific region of a chromosome, is consistently inherited along with the disease …

—Leslie Roberts, Science

called also marker gene