tonic sol-fa

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. Music A system of notation that is based on relationships between tones in a key and that replaces the usual staff notation with solmization syllables, such as do, re, and mi, or their abbreviations.

GNU Webster's 1913

1. n. (Mus.) the name of the most popular among letter systems of notation (at least in England), based on key relationship, and hence called “tonic.” Instead of the five lines, clefs, signature, etc., of the usual notation, it employs letters and the syllables do, re, mi, etc., variously modified, with other simple signs of duration, of upper or lower octave, etc. See Sol-fa.

WordNet 3.0

1. n. a system of solmization using the solfa syllables: do, re, mi, fa, sol, la, ti