And the "proof" used is an archaic term that means "test". The same word occurs in discussing alcohol strength ("100 proof") and in "proof standard" (the standa

And the "proof" used is an archaic term that means "test". The same word occurs in discussing alcohol strength ("100 proof") and in "proof standard" (the standard[1] that you use to compare against). The German cognate would be "prüfen", the Swedish probably "pröva". So, the exception tests the rule. [1] And the standard is, of course, a reference exemplar of some sort.