sol-fa: [16] Sol-fa is a lexicalization of two of the syllables (sol and fa) used in the tonic sol-fa system for representing the notes of the musical scale. In Italian the combination was turned into a verb, solfeggiare, a derivative of which has given English solfeggio ‘use of the sol-fa system’ [18]. (Another English word based on the name of notes of the scale is gamut.) [sol-fa etymology, sol-fa origin, 英语词源]