"Harmonious" is the Engpsh word for "和谐" in Chinese. The word "harmonious" comes from the Latin word "harmonia" which means "agreement" or "concord".
For example:
The team worked in harmonious cooperation. (这个团队和谐地合作。)
The music creates a harmonious atmosphere in the room. (音乐在房间里创造了一种和谐的氛围。)
They have a harmonious relationship. (他们有着和谐的关系。)