The Collaborative International Dictionary of English v.0.48:
Melody \Mel"o*dy\, n.; pl. Melodies. [OE. melodie, F.
m['e]lodie, L. melodia, fr. Gr. ? a singing, choral song, fr.
? musical, melodious; me`los song, tune + ? song. See Ode.]
1. A sweet or agreeable succession of sounds.
Lulled with sound of sweetest melody. --Shak.
2. (Mus.) A rhythmical succession of single tones, ranging
for the most part within a given key, and so related
together as to form a musical whole, having the unity of
what is technically called a musical thought, at once
pleasing to the ear and characteristic in expression.
Note: Melody consists in a succession of single tones;
harmony is a consonance or agreement of tones, also a
succession of consonant musical combinations or chords.
3. The air or tune of a musical piece.
Syn: See Harmony.