potomac has 1 distinct synonym spread across 1 of its 2 senses. Each sense below keeps its own list, because a synonym belongs to a meaning and not to a word: swapping one sense's substitute into another sense's sentence is how a thesaurus makes writing worse. WordNet records no antonym for it — antonymy is a relation between word forms rather than concepts, so it is deliberately sparse.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
a river in the east central United States; rises in West Virginia in the Appalachian Mountains and flows eastward, forming the boundary between Maryland and Virginia, to the Chesapeake Bay
term sometimes used to refer to Washington, D.C.
Synonyms, antonyms and the broader and narrower relations for potomac come from Princeton University’s WordNet. Full sources and licences.