sol

I. noun also so Etymology: Medieval Latin sol; from the syllable sung to this note in a medieval hymn to Saint John the Baptist Date: 14th century the fifth tone of the diatonic scale in solmization II. noun Etymology: Middle French — more at sou Date: 1583 an old French coin equal to 12 deniers; also a corresponding unit of value III. noun (plural soles) Etymology: American Spanish, from Spanish, sun, from Latin Date: 1883 the basic monetary unit of Peru before 1985 and since 1990 — see money table IV. noun Etymology: -sol (as in hydrosol), from solution Date: 1899 a fluid colloidal system; especially one in which the continuous phase is a liquid V. abbreviation soluble