1.simultaneous performance of action or utterance of speech."
“Yes, sir,” said the girls in unisun"
Similar:simultaneouslyat (one and) the same time(all) at onceat the same moment(all) togetheras onein concertin chorus
2.MUSIC coincidence in pitch of sounds or notes."the flutes play in unisun with the violas"
definitions in: All Physics Mathematics Technology
noun1 .the state, fact, quality, or condition of being singular."he believed in the singularity of all cultures"