Added 10 October 2026 sealant /ˈsiːlənt/ noun Categories: NatureRare Words noun ! Definition from Wiktionary (CC BY-SA). Pronunciation from Wiktionary, via Kaikki.org. More about sealant at Wordnik → Where our words come from → Any material used to seal a surface so as to prevent passage of a fluid. A mixture of polymers, fillers, and pigments used to fill and seal joints where moderate movement is expected. Related Words: sealercoatingwaterproofwatertightbubblesiliconsiliconesealcaulkspoogeseeper Back to today's word