In Japan we use the word "調和(ちょうわ-chouwa)" for the English word "Harmony". And we have a couple of other words which related this Japanese word "調和". Here are examples; "和合(わごう-wagou)" and "和声(わせい-wasei)". Even though both of these words are translated as ""Harmony", the word "和合" is mainly used for the relationship between people and the word "和声" is used in the field of music.
The word "調和" is the most popular word when we translate "Harmony" into Japanese and is used widely in any occasion.