Meaning

noun a colloid that has a continuous liquid phase in which a solid is suspended in a liquid

noun (Roman mythology) ancient Roman god; personification of the sun; counterpart of Greek Helios

noun the syllable naming the fifth (dominant) note of any musical scale in solmization

originFrom Glover's solmization, from Middle English sol (“fifth degree or note of Guido of Arezzo's hexachordal scales”), Italian sol in the solmization of Guido of Arezzo, from the first syllable of Latin solve (“wash away”) in the lyrics of the scale-ascending hymn Ut queant laxis by Paulus Deacon.

Etymology from Wiktionary, CC BY-SA 3.0