WordNet records no synonym and no antonym for socket. It is the only member of each of its synsets, which is common for technical, taxonomic and single-sense vocabulary — there is no other English word that means the same thing. The broader and narrower terms below are the useful relations in that case.
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 bony hollow into which a structure fits
receptacle where something (a pipe or probe or end of a bone) is inserted
Synonyms, antonyms and the broader and narrower relations for socket come from Princeton University’s WordNet. Full sources and licences.
a receptacle into which an electric device can be inserted