solmization

[sol-muh-zey-shuh n, sohl-] /ˌsɒl məˈzeɪ ʃən, ˌsoʊl-/
noun, Music.
1.
the act, process, or system of using certain syllables, especially the sol-fa syllables, to represent the tones of the scale.
Origin
1720-30; < French solmisation, equivalent to solmis(er) (sol sol1 + mi mi + -iser -ize) + -ation -ation
British Dictionary definitions for solmization

solmization

/ˌsɒlmɪˈzeɪʃən/
noun
1.
(music) a system of naming the notes of a scale by syllables instead of letters derived from the 11th-century hexachord system of Guido d'Arezzo, which assigns the names ut (or do), re, mi, fa, sol, la, si (or ti) to the degrees of the major scale of C (fixed system) or (excluding the syllables ut and si) to the major scale in any key (movable system) See also tonic sol-fa
Word Origin
C18: from French solmisation, from solmiser to use the sol-fa syllables, from sol1 + mi
Word Origin and History for solmization
n.

"act of using certain syllables to name tones of a music scale," 1730, from French solmisation, from solmiser, from sol + mi, two of the syllables so used (see gamut).