[opera] pl of opus
[2]op.era n [It, work, opera, fr. L, work, pains; akin to L oper-, opus--more at operate] (1644) 1: a drama set to music and made up of vocal pieces with orchestral accompaniment and orchestral overtures and interludes; specif: grand opera
2: the score of a musical drama
3: the performance of an opera; also: a house where operas are performed