From Longman Dictionary of Contemporary Englishunisonu‧ni‧son /ˈjuːnəsən, -zən/ noun → in unison
Examples from the Corpus
unison• The office fellows on the table behind laughed abruptly and in unison.• All consider that good and evil can not be in unison.• They deserve to be listed in this context, as they often operate in unison even if they do not always do so.• While her class was reciting in unison you could not hear very much in mine.• It only needed two men working in unison to raise and lower the junk sails to suit the wind strength.• Stephen Legate looked out of phase in the unison tableaux.Origin unison (1500-1600) Old French Medieval Latin unisonus “having the same sound”, from Latin uni- + sonus “sound” 