hairline

noun

hair·​line ˈher-ˈlīn 

1

: a very slender line: such as

a

: a tiny line or crack on a surface

a hairline bone fracture

b

: a fine line connecting thicker strokes in a printed letter

2

: hairbreadth

3

a

: a textile design consisting of lengthwise or crosswise lines usually one thread wide

b

: a fabric with such a design

4

a

: the outline of scalp hair especially on the forehead

b

: the way the hair frames the face

hairline adjective

Synonyms

• inch
• neck
• hair
• step

Examples of hairline in a Sentence

The plate had a hairline running across it.

He has a receding hairline.

Recent Examples on the Web

Consultations start with an honest evaluation of the donor area, followed by a hairline design that respects facial features and age. —Maria Williams, USA Today, 6 Oct. 2025

Last week, at the Glasgow stop of her Infinity Heart tour, Siwa unexpectedly ejected two fans from the show over a hoodie that featured Siwa photoshopped onto an egg, an image that appeared to be mocking her hairline. —Shania Russell, Entertainment Weekly, 6 Oct. 2025

The hidden risks Not every story ends with a perfect hairline. —Rebecca Rosman, NPR, 6 Oct. 2025

One player absent from the series was catcher Will Smith, who suffered a hairline fracture in his throwing hand in early September. —Shaun McAvoy, MSNBC Newsweek, 3 Oct. 2025

Word History

First Known Use

1846, in the meaning defined at sense 1

Rhymes for hairline

• affine
• airline
• align
• aline
• assign
• baseline
• beamline
• benign
• bloodline
• bovine
• byline
• canine

Kids Definition

hairline

noun

hair·​line ˈha(ə)r-ˌlīn 

ˈhe(ə)r-

1

a

: a very slender line

b

: a very thin crack on a surface

a hairline bone fracture

2

: the outline of the hair on the head and especially on the forehead

hairline adjective

Medical Definition

hairline

noun

hair·​line -ˈlīn 

: the outline of scalp hair especially on the forehead

hairline adjective