From the Wordsmith word-a-day list:
gamut (GAM-uht) noun
The complete range of something.
[From Medieval Latin, contraction of gamma ut, from gamma (third letter of the Greek alphabet), used to represent the lowest tone + ut, from the names of the notes ut, re, mi, fa, sol, la, si (ut and si later changed to do and ti). Gamma + ut contracted to gamut and the meaning expanded to denote all notes. The names ut, re, mi, fa, sol, la, si are derived from the initial syllables of a Latin hymn.]