unison
n. uncountablen. the act of doing or saying something at the exact same time as other people. In music, it means everyone sings or plays the same note together.
n. the simultaneous performance of action or utterance of words. In a musical context, refers to the sounding of the same pitch or its octave by multiple voices or instruments.
The crowd shouted their approval in unison.
The dancers moved in perfect unison, making the complex choreography look effortless to the audience.
While the choir usually performs in four-part harmony, they sang the final verse in unison to create a powerful, singular wall of sound that filled the cathedral.
From Middle English unisoun, from Middle French unisson, from Medieval Latin ūnisonus (“having the same sound”), from ūni- + sonus (“sound”).
Almost always used in the prepositional phrase 'in unison'.