Added 9 October 2026 waterline /ˈwɔːtə(ɹ)laɪn/ noun Categories: PlacesRare Words noun ! Definition from WordNet 3.1, Princeton University. Pronunciation from Wiktionary, via Kaikki.org. More about waterline at Wordnik → Where our words come from → A line corresponding to the surface of the water when the vessel is afloat on an even keel; often painted on the hull of a ship. Origin From water + line. From Wiktionary, via Kaikki.org (CC BY-SA) Related Words: floatationflotationbuoyancyflowlinewalewaistlinegunwale Back to today's word