Wago (和語; Japanese pronunciation: [waꜜɡo]) are native Japanese words, meaning those words in Japanese that have been inherited from Old Japanese, rather than being borrowed at some stage. Together with kango (漢語) and gairaigo (外来語), they form one of the three main sources of Japanese words (there is also elaborate Japanese sound symbolism, of mimetic origin). They are also known as yamato kotoba (大和言葉; [jamatokoꜜtoba]).
The word yamato kotoba itself is composed of native Japanese words, and hence is an autological word. The synonym wago is instead a kango, and hence a heterological word.