Not just Japanese - many languages use the same word for "green" and "blue". Linguists call it "grue". https://en.wikipedia.org/wiki/Blue%E2%80%93green_distinc

Not just Japanese - many languages use the same word for "green" and "blue". Linguists call it "grue". https://en.wikipedia.org/wiki/Blue%E2%80%93green_distinction_in_language https://en.wikipedia.org/wiki/Blue%E2%80%93green_distinction... E.g. the Vietnamese word xanh means "grue", and to distinguish between green and blue you say "sky xanh" or "leaf xany".