Chemistry and materials

Two thirds of the way down sits le solvant, which looks like « solvent » and is one — except that the English word has a second life the French one is kept out of. A firm described as « solvent » holds no liquid at all: it can pay what it owes. Both senses come from Latin solvere, to loosen or untie, a verb that did two jobs at once, undoing a knot and discharging a debt, because paying releases the payer. From the first job English has « dissolve », « solution » and the chemist’s « solvent »; from the second, « absolve », « resolve » and the accountant’s « solvent ». French took the same verb and gave each job its own ending, so the two never meet: le solvant belongs to the bench, solvable belongs to the bank, and a firm that can pay its bills is solvable, never solvant. The trap turns round at the end of this list, because soluble — there for a powder in cold water — also does the work of English « solvable », as in un problème soluble.