WordNet records no synonym and no antonym for apophysis. 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.
(botany) a natural swelling or enlargement: at the base of the stalk or seta in certain mosses or on the cone scale of certain conifers
(anatomy) a natural outgrowth or projection on an organ or body part such as the process of a vertebra
Synonyms, antonyms and the broader and narrower relations for apophysis come from Princeton University’s WordNet. Full sources and licences.