receptor has 2 distinct synonyms 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. Its one recorded opposite is effector.
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 cellular structure that is postulated to exist in order to mediate between a chemical agent that acts on nervous tissue and the physiological response
an organ having nerve endings (in the skin or viscera or eye or ear or nose or mouth) that respond to stimulation
Synonyms, antonyms and the broader and narrower relations for receptor come from Princeton University’s WordNet. Full sources and licences.