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 of hairline

• inch
• hair
• neck
• 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

Tucker sustained a hairline fracture in his right hand during a slide into second base against the Cincinnati Reds on June 1 last year, Cubs manager Craig Counsell confirmed to ESPN at the time. — Skyler Caruso, PEOPLE, 4 Aug. 2026

Few physical changes are as distressing as noticing your hairline receding, your part widening or a once-full head of hair becoming noticeably thinner. — Daryl Austin, USA Today, 31 July 2026

Bettmann Archive Most people’s hairlines run more or less straight across the forehead. — Scott Travers, Forbes.com, 28 July 2026

This is the Micro Sapphire DHI, aiming for tighter graft placement and a natural hairline. — Sacbee.com, 22 July 2026

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
• brucine
• byline

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