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

Just weeks after winning the 2020 election, Biden suffered a hairline fracture on his foot while playing with one of his dogs. —Peter Suciu, Forbes.com, 12 June 2025

But even before Saturday, Alvarado had already pulled off an upset of his own, bouncing back from a hairline fracture in his shoulder two months ago that left him sidelined for weeks. —Elizabeth Robinson, NBC news, 5 May 2025

Every year, our editors are presented with countless new products that claim to do everything from restoring hairlines to reversing age spots, wrinkles, and more. —Justin Fenner, Robb Report, 13 June 2025

Townsend’s go-to trick for a polished finish is to spritz a bit of strong-hold spray on a clean toothbrush to tame edges around the hairline or nape. —Michelle Rostamian, Allure, 6 June 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