TonganPronunciation: /ˈtɒŋən, ˈtɒŋg(ə)n/Definition of Tongan adjective relating to Tonga or its people or language. noun 1a native or inhabitant of Tonga. 2 [mass noun] the Polynesian language spoken in Tonga. Tongan in other Oxford dictionaries Definition of Tongan in the US English dictionary