unison >> ˈjuːnɪs(ə)n
Definition: [noun] simultaneous performance or utterance of action or speech.
Example: ‘Yes, sir,’ said the girls in unison
Definition: [noun] coincidence in pitch of sounds or notes.
Example: the flutes play in unison with the violas
Definition: [adjective] performed in unison.
Example: unison congregational singing