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

Diagnosis depends on combining clinical findings with multiple laboratory markers, which is why doctors often pull from several tests rather than relying on one number. —Samantha Agate, Sacbee.com, 4 June 2026

Eastland survivor Libby Hruby told those assembled for the dedication of the marker on June 4, 1989, that she was plucked from the water by her sister. —Kori Rumore, Chicago Tribune, 4 June 2026

Sabaliauskas said resting heart rate and heart rate variability, or HRV, are the two markers the company tracks. —Samantha Agate, Kansas City Star, 4 June 2026

The shell casings surrounding the car were seen on the shoulder and in several lanes of the expressway — with officers putting down dozens of evidence markers. —Asal Rezaei, CBS News, 4 June 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