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

There was also the recent disclosure that Tucker was diagnosed with a hairline fracture in his right hand back in June, which turned out to be his best month as a Cub. —Patrick Mooney, New York Times, 8 Sep. 2025

Pelphrey leaned into the look, with Ingelsby’s encouragement, especially because of his roots — the East Coast ones, not his hairline. —Emily Longeretta, Variety, 3 Sep. 2025

And a very close look at Halsey's hairline seems to reveal that her hair is definitely dyed. —Marci Robin, Allure, 1 Sep. 2025

His clinic is renowned for providing the best care, specializing in natural hairline design and minimally invasive FUE and DHI treatments. —Matt Emma, USA Today, 27 Aug. 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