和聲演唱，和弦演奏

harmonise(verb)

to sing or play musical instruments in harmony.

加上不同樂音以形成和聲(弦)

harmonise(verb)

to add different parts to (a melody) to form harmonies.

(使)調合

harmonise(verb)

to (cause to) be in harmony or agreement

The colours in this room harmonize nicely.