potus

Potus, potus, m., fourth declension. It covers both the act of drinking and the thing drunk, and it pairs with cibus so reliably that cibus et potus is a fixed phrase for board and keep in a monastic rule. Fourth declension gives ablative singular potu and accusative potum.

The form is the trap. Potus is also the perfect participle of poto, and unusually for a participle in -tus it is active in sense: potus homo is a man who has been drinking, not a man who has been drunk by something. Bibo is the everyday verb for drinking; poto suggests doing it seriously. English kept potion and potable from the family, and, at a longer remove and through Old French, poison - which began as nothing worse than a draught.