aegospotamos has 1 distinct synonym spread across 2 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 creek emptying into the Hellespont in present-day Turkey; at its mouth in 405 BC the Spartan fleet under Lysander defeated the Athenians and ended the Peloponnesian War
a river in ancient Thrace (now Turkey); in the mouth of this river the Spartan fleet under Lysander destroyed the Athenian fleet in the final battle of the Peloponnesian War (404 BC)
Synonyms, antonyms and the broader and narrower relations for aegospotamos come from Princeton University’s WordNet. Full sources and licences.