frequency has 4 distinct synonyms spread across 3 of its 3 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.
the number of occurrences within a given time period
“the frequency of modulation was 40 cycles per second”
Synonyms, antonyms and the broader and narrower relations for frequency come from Princeton University’s WordNet. Full sources and licences.
the ratio of the number of observations in a statistical category to the total number of observations
the number of observations in a given statistical category