Noah Webster's Dictionary 1. (n.) Harmony; agreement; concord; union. 2. (n.) Identity in pitch; coincidence of sounds proceeding from an equality in the number of vibrations made in a given time by two or more sonorous bodies. Parts played or sung in octaves are also said to be in unison, or in octaves. 3. (n.) A single, unvaried. 4. (n.) Sounding alone. 5. (n.) Sounded alike in pitch; unisonant; unisonous; as, unison passages, in which two or more parts unite in coincident sound.

Multi-Version Concordance Unison (2 Occurrences) Acts 19:34 But when they perceived that he was a Jew, all with one voice for a time of about two hours cried out, "Great is Artemis of the Ephesians!" (See NIV) 2 Chronicles 5:13 it happened, when the trumpeters and singers were as one, to make one sound to be heard in praising and thanking Yahweh; and when they lifted up their voice with the trumpets and cymbals and instruments of music, and praised Yahweh, saying, For he is good; for his loving kindness endures forever; that then the house was filled with a cloud, even the house of Yahweh, (See NAS RSV NIV)