Pronunciation (UK) IPA (key): /ˈruːstə/ (US) enPR: roo͞'stər, IPA (key): /ˈrustər/ Audio (US)(file) Audio (AU)(file) Noun Singular rooster Plural roosters A rooster is an adult male chicken. Synonym: cock The rooster crowed loudly every morning. Wikiwand - on Seamless Wikipedia browsing. On steroids.Remove ads