n. 1 a a dramatic work in one or more acts, set to music for singers (usu. in costume) and instrumentalists. b this as a genre. 2 a building for the performance of opera. opera-glasses small binoculars for use at the opera or theatre. opera-hat a man's tall collapsible hat. opera-house a theatre for the performance of opera.
[ It. f. L, = labour, work ]