solmisation

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun a method of sight singing music that uses the syllables do (originally ut), re, mi, fa, sol (or so), la, and si (or ti) to represent the pitches of the scale, most commonly the major scale. The fixed-do system uses do for C, and the moveable-do system uses do for whatever key the melody uses (thus B is do if the piece is in the key of B).

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a system of naming the notes of a musical scale by syllables instead of letters