American Heritage Dictionary
(3)
Century Dictionary
(7)
GNU Webster's 1913
(3)
WordNet
Elsewhere on the web
Now, perhaps we had better sol-fa the tune.— Two on a Tower
This being done the pupil is to begin his studies by _sol-fa_-ing the scales.— The Psychology of Singing A Rational Method of Voice Culture Based on a Scientific Analysis of All Systems, Ancient and Modern
Then they all learned songs together from tonic sol-fa, singing in a circle round the fire.— Sons and Lovers
Gate, and with them he learnt the sol-fa-ing gamut on the old— Self help; with illustrations of conduct and perseverance
Here is a pun on 'wring' and 'ring'; and 'sol-fa' is used as an equivalent for 'sing.'— Shakespeare and Music With Illustrations from the Music of the 16th and 17th centuries

American Heritage Dictionary (1)
Century Dictionary (2)
Bubble size: how much this word was used in a year
Bubble height: used more or less than expected, vs. all uses evenly distributed
We are still working on calculating this word's frequency.