c. 1300, melodie, "vocal or instrumental music, a succession of agreeable musical sounds," from Old French melodie "music, song, tune" (12c.) and directly from Late Latin melodia "a pleasant song" (in Medieval Latin also "music" generally), from Greek melōidia "a singing, a chanting; a choral song, a tune for lyric poetry," from melos "song, part of song; limb, member" (a word of uncertain origin) + ōidē "song, ode" (see ode). From late 14c. as "a song of clear and balanced form." Sense of "a series of tones so related to one another as to produce a distinct musical phrase or idea, a tune" is by c. 1600. Meaning "the principal voice-part in a harmonic composition" is by 1880.
"containing or characterized by melody, agreeable to the ear," late 14c., from Old French melodios "melodious; delightful" (French mélodieux), from Medieval Latin melodiosus, from Latin melodia (see melody). Related: Melodiously; melodiousness.
1847, originally of a type of reed organ, variant of melodion, from German Melopdoin, from Melodie, from Old French melodie (see melody). As "a music hall" by 1840.
1818, "melodious;" by 1823, "pertaining to the melody" (as distinguished from the harmony), from French mélodique, from Late Latin melodicus, from Greek melodikos, from melodia (see melody). Related: Melodical "melodious" (1590s).
In early 19th century use, a stage-play (usually romantic and sentimental in plot and incident) in which songs were interspersed and in which the action was accompanied by orchestral music appropriate to the situations. In later use the musical element gradually ceased to be an essential feature of the 'melodrama', and the name now denotes a dramatic piece characterized by sensational incidents and violent appeals to the emotions, but with a happy ending. [OED]
The shift toward "a romantic and sensational dramatic piece with a happy ending" is evident by 1883. Also from French are Spanish melodrama, Italian melodramma, German melodram. Related: Melodramatize.
The melodramatist's task is to get his characters labelled good & wicked in his audience's minds, & to provide striking situations that shall provoke & relieve anxieties on behalf of poetic justice. [Fowler]
1837, "a melodic decoration consisting of the prolongation of one syllable over a number of notes," from Greek melisma "a song, an air, a tune, melody," from melos "music, song, melody; musical phrase or member," literally "limb," a word of uncertain origin. Related: Melismatic.