With origin in the Latin word unisŏnus, the term unison refers to what the same sound or tone what other element. The concept can also be used to name the musical fragment with instruments or voices that sound in equal tones.
When two tones have identical heightAlthough they are perceived as coming from different sources, they are tones in unison. Unison can be said to be a type of musical interval.
Two instruments playing the same note at the same time are sounding in unison. This generates two notes that, although they are the same, can have different doorbells, so it is possible to differentiate them.
Suppose that with an acoustic guitar and a keyboard you play a certain melody. Both instruments sound simultaneously and in unison, but guitar notes on one side and keyboard notes on the other can be recognized and distinguished.
It is usual that, in a chorus, all the members sing in unison. As we explained above, this assumes that all the choristers interpret the same notes.
As an adverbial phrase, meanwhile, the expression “In unison” makes mention of what it is expressed or carried out unanimously, without there being divergences or disagreements. By example: “When the mayor left the premises, hundreds of people who were in the street booed him in unison and asked for his resignation”, “We are going to work together to solve this problem as soon as possible”, “Thousands of young people lived the legendary artist in unison and showed him their admiration”.