early 15c., "act or process of becoming liquid," from French liquéfaction, from Late Latin liquefactionem (nominative liquefactio), noun of action from past-participle stem of Latin liquefacere "to make liquid, melt" (see liquefy). Formerly also used in a metaphysical sense, of the melting of the soul in the ardor of devotion. Related: Liquefacient.
Whenas in silks my Julia goes,
Then, then (methinks) how sweetly flows
That liquefaction of her clothes.
[Robert Herrick (1591-1647)]
late 14c. dissolven, "to break up, disunite, separate into parts" (transitive, of material substances), also "to liquefy by the disintegrating action of a fluid," also intransitive, "become fluid, be converted from a solid to a liquid state," from Latin dissolvere "to loosen up, break apart," from dis- "apart" (see dis-) + solvere "to loosen, untie," from PIE *se-lu-, from reflexive pronoun *s(w)e- (see idiom) + root *leu- "to loosen, divide, cut apart."
General sense of "to melt, liquefy by means of heat or moisture" is from late 14c. Meaning "to disband" (a parliament or an assembly) is attested from early 15c. Related: Dissolved; dissolving.