primary colour for light has 1 distinct synonym spread across 1 of its 1 sense. 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.
any of three primary colors of light from which all colors can be obtained by additive mixing
“the primary colors for light are red, blue, and green”
Synonyms, antonyms and the broader and narrower relations for primary colour for light come from Princeton University’s WordNet. Full sources and licences.