Added 9 October 2026 hairline /ˈhɛɹˌlaɪn/ noun Categories: LanguageThe BodyRare Words noun ! Definition from WordNet 3.1, Princeton University. Pronunciation from Wiktionary, via Kaikki.org. More about hairline at Wordnik → Where our words come from → A very thin line. The natural margin formed by hair on the head. Origin From hair + line. From Wiktionary, via Kaikki.org (CC BY-SA) Related Words: foreheadhaircuthaircuttingcutstumpagecupgobletcouperecedingbrowline Back to today's word