The Collaborative International Dictionary of English v.0.48:

Operatic \Op`er*at"ic\, Operatical \Op`er*at"ic*al\, a.
   Of or pertaining to the opera or to operas; characteristic
   of, suitable for, or resembling, the opera; as, an operatic
   voice.
   [1913 Webster +PJC]

WordNet (r) 3.0 (2006):

operatic
    adj 1: of or relating to or characteristic of opera

Moby Thesaurus II by Grady Ward, 1.0:

56 Moby Thesaurus words for "operatic":
   actor-proof, all-star, alto, ballet, balletic, baritone, bass,
   bravura, choral, choric, cinematic, cinematographic, coloratura,
   dramatic, dramatical, dramaturgic, falsetto, film, filmic, ham,
   hammy, heroic, histrionic, hymnal, legitimate, liturgical, lyric,
   melodramatic, milked, monodramatic, movie, overacted, overplayed,
   psalmic, psalmodial, psalmodic, sacred, scenic, singing, soprano,
   spectacular, stagelike, stageworthy, stagy, starstruck, stellar,
   tenor, theaterlike, theatrical, thespian, thrown away, treble,
   underacted, underplayed, vaudevillian, vocal