noun
- the edge of the hair on the head, especially on the forehead
- a very thin line or crack
adjective
- extremely thin or fine
Examples
- His hairline was receding as he got older.
- She noticed a hairline crack in the vase.
- The engineer detected a hairline fracture in the metal beam.
- The artist drew with hairline precision.
- There was a hairline difference between the two measurements.
- The hairline on his forehead was perfectly straight.
- A hairline scratch appeared on the phone screen.