• chromatic scale: an instrument for weighing that indicates half-pounds.
• bar line: a gathering of people, usually among which may be found a musician or two.
• ad libitum: a premiere.
• beat: what music students do to each other with their instruments. The down beat is performed on top of the head, while the up beat is struck under the chin.
• cadence: when everybody hopes you're going to stop, but you don't.
• diatonic: low-calorie Schweppes.
• lamentoso: with handkerchiefs.
• virtuoso: a musician with very high morals. (I know one)
• music: a complex organizations of sounds that is set down by the composer, incorrectly interpreted by the conductor, who is ignored by the musicians, the result of which is ignored by the audience.
• oboe: an ill wind that nobody blows good.
• tenor: two hours before a nooner.
• diminished fifth: an empty bottle of Jack Daniels.
• perfect fifth: a full bottle of Jack Daniels.
• ritard: there's one in every family.
Link:
http://www.mit.edu/~jcb/other-instrument-jokes.html