nativismPronunciation: /ˈneɪtɪvɪz(ə)m/Definition of nativism noun [mass noun] 1the theory that concepts, mental capacities, and mental structures are innate rather than acquired by learning. 2chiefly US the policy of protecting the interests of native-born or established inhabitants against those of immigrants. 3a return to or emphasis on indigenous customs, in opposition to outside influences. Derivatives nativist noun & adjective nativistic adjective nativism in other Oxford dictionaries Definition of nativism in the US English dictionary