The term also applies to almost any music group such as a band choir and trio this term is also known as a cooperative expression

The term is harmony.

Explanation:

The word harmony is used to refer to and order arrangement of voice parts. It can also refer (musically) to the simultaneous mixture of tones, or sounds (especially when blended into musical chord) such that it is pleasing to the ear;

When used as a cooperative expression, it means working together towards a common goal or having congruous relationship with other people.

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ive noticed that too but is this a question