Definition of melodrama:
(n) :
a kind of drama having a musical accompaniment to intensify the effect of certain scenes (archaic); a drama abounding in romantic sentiment and agonizing situations, with a musical accompaniment only in parts which are especially thrilling or pathetic. In opera, a passage in which the orchestra plays a somewhat descriptive accompaniment, while the actor speaks; as, the melodrama in the grave digging scene of Beethoven's "Fidelio"