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

The hygienist told me there were hairline fractures along the tops of my teeth. — Literary Hub, 9 Sep. 2026

In interviews back then, Musk comes off as awkward, a geek in pleated khakis with a receding hairline and uneven teeth. — Matthew Carey, Deadline, 8 Sep. 2026

In March 2024, hairline cracks began forming along the entire length of a support beam on the top floor. — Susannah Bryan, Sun Sentinel, 6 Sep. 2026

Symptoms can include a high fever, cough, runny nose, red/watery eyes, white spots inside the mouth and a rash that begins on the face at the hairline and moves downward on the body. — Finch Walker, USA Today, 2 Sep. 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