Pianoforte - "Soft-loud." A keyboard instrument, the full name for the piano, on which sound is produced by hammers striking strings when keys are pressed. It has 88 keys.
Rinforzando - A reinforced accent.
Senza - Without. Used with other terms, e.g. senza crescendo.
Third - The third degree of the diatonic scale. Also, the interval formed by a given tone and the third tone above or below it, e.g. c up to e, or c down to a. Intervals of the third may be major, minor, diminished, or augmented.
Aleatory, or aleatoric music - Chance music in which the performers are free to perform their own material and/or their own manner of presentation.