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 line was drawn up under the 1953 armistice that stopped the fighting of the Korean War, and some decades-old boundary markers have been lost over time. — Arkansas Online, 24 Oct. 2026

New historical markers also recognize the history of the site and surrounding areas as a community hub for Charlotte’s Black residents dating back to the 1920s, as well as the park’s namesake. — Mary Ramsey, Charlotte Observer, 22 Oct. 2026

The burden of meeting all these parameters has pushed researchers to pinpoint MRI markers that can better help distinguish MS from everything else, Bebo said. — Erica Sloan, Washington Post, 22 Oct. 2026

After the 2023 carnage, the Metropolitan Pier and Exposition Authority (which owns and operates the center) applied visible markers — a film of tiny dots — to the glass, reducing bird collisions by 95%, according to an analysis by the Field Museum. — Adriana Pérez, Chicago Tribune, 22 Oct. 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