Word parts lime + stone Pronunciation (UK) IPA (key): /ˈlaɪmˌstoʊn/ (US) IPA (key): /ˈlaɪmˌstəʊn/ Audio (UK)(file) Noun Singular limestone Plural limestones Limestone is a white or light grey rock that is used as a building material and in the making of cement. Wikiwand - on Seamless Wikipedia browsing. On steroids.Remove ads