Unison – Playing two or more musical parts which are either identical or separated by an octave simultaneously
To remember what unison means, use the following mnemonic:
While on unicycles, the two identical sons (unison) sang the same tunes.
Note: Music that is unison occurs when two or more people play or sing the same tune either in the same pitch or different octaves. Many choirs are taught to sing in unison. "Unison" is all the singers singing the same melody.
Unison literally means "one sound" in Latin, and directs participants to play or sing the same notes together, or "as one".
Harmony means "different" in Latin, and directs participants to produce different notes together, creating a pleasant "chord" or harmony.