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

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

That means focusing primarily on the roots and areas where oil tends to accumulate, such as the crown, hairline and part. — Daryl Austin, USA Today, 25 July 2026

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

This can be interpreted many ways, from glitter parts and rhinestone placements to artistic hairlines and cuffed bubble braids. — Daisy Maldonado, InStyle, 20 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