The Japanese word wa is a single kanji meaning "harmony; peace; peaceful." In common usage wa means "harmony" as in being in harmony with one's environment and it means "peaceful" as in being in a peaceful state of mind or feeling at peace.
As an aside, in combination with other kanjiwa can mean "Japan" or "Japanese style" (as an example, the word Japanese Cuisine (washoku) means "Japanese cuisine").
The Japanese word 調和 is composed of the kanji調 (read chou) meaning "investigate; prepare; tune; tone" and 和 (read wa) meaning "harmony; peace; Japanese Style".
This is not harmony in the musical sense of "tuneful sounds", but rather is harmony in the sense of "tranquility".