pile has 37 distinct synonyms spread across 10 of its 11 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 collection of objects laid on top of each other
battery consisting of voltaic cells arranged in series; the earliest electric battery devised by Volta
a column of wood or steel or concrete that is driven into the ground to provide support for a structure
a nuclear reactor that uses controlled nuclear fission to generate energy
press tightly together or cram
“The crowd packed the auditorium”
Synonyms, antonyms and the broader and narrower relations for pile come from Princeton University’s WordNet. Full sources and licences.
place or lay as if in a pile
“The teacher piled work on the students until the parents protested”