mid-14c., "frivolity, moral laxness, dissolute living;" late 14c., dissolucioun, "separation into parts, dispersal;" from Old French dissolution (12c.) and directly from Latin dissolutionem (nominative dissolutio) "a dissolving, destroying, interruption, dissolution," noun of action from past-participle stem of dissolvere "to loosen up, break apart" (see dissolve).
Sense of "act of dissolving, a changing from a solid to a liquid state" is from 1590s. From 1530s as "the breaking up of an assembly or other association." From 1520s as "death," perhaps from the notion of "separation of soul and body."