Pronunciation (UK) IPA (key): /ˈmɪʃ(ə)n/ (US) enPR: mĭshʹən or mĭshʹn, IPA (key): /ˈmɪʃ(ə)n/ Audio (US)(file) Hyphenation: mis‧sion Noun Singular mission Plural missions (countable) A mission is a quest given by someone to gain something. Synonym: quest The Interpol is on a mission to find the international terrorists.Wikiwand - on Seamless Wikipedia browsing. On steroids.Remove ads