WordNet records no synonym and no antonym for sorus. 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 spore-producing structure in certain lichens and fungi
cluster of sporangia usually on underside of a fern frond
Synonyms, antonyms and the broader and narrower relations for sorus come from Princeton University’s WordNet. Full sources and licences.