Added 9 October 2026 fibreglass /ˈfaɪbəɡlɑːs/ noun Categories: NatureRare Words noun ! Definition from Wiktionary (CC BY-SA). Pronunciation from Wiktionary, via Kaikki.org. More about fibreglass at Wordnik → Where our words come from → Silica based glass extruded into fibers that possess a length at least 1000 times greater than their width. Ellipsis of fibreglass wool. A composite material made from fine fibres of spun glass held together with resin. verb To apply fibreglass to. to fibreglass the hull of a fishing boat Origin Compound of fibre + glass. From Wiktionary, via Kaikki.org (CC BY-SA) Related Words: fiberglassglassfiberdrinkfibrefibrolinefibrecraftfilamentglasswoolprotofiber Back to today's word