Music.the set of syllables, do, re, mi, fa, sol, la, and ti, sung to the respective tones of the scale. All but do and ti are attributed to Guido d'Arezzo.
2.
the system of singing tones to these syllables.
verb (used without object)
3.
to use the sol-fa syllables in singing, or to sing these syllables.
1548, from It., from M.L. sol + fa, two notes of the musical scale. Related to solfeggio "use the sol-fa system" (1774), from It. solfeggiare (see gamut).