Wikimedia Commons has media related to: Boulder Pronunciation (UK) IPA (key): /ˈbəʊl.də(r)/ (US) IPA (key): /ˈboʊldər/ Audio (US)(file) Homophone: bolder Noun Singular boulder Plural boulders (countable) A boulder is a large piece of stone or rock. Wikiwand - on Seamless Wikipedia browsing. On steroids.Remove ads