Dilettante’s Dictionary: Audio terminology in these digital days. It seems a good dictionary of audio and music terms.
song: (1) Strictly, a piece of solo vocal music, with or without accompaniment, and of short duration. In popular music, this has come to mean any music which is sung. (2) A synonym for a sequence, i.e., a selection of MIDI performance data recorded on a sequencer.
(via Bifurcated Rivets)