Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
all-or-none is an adjective meaning "occurring completely or not occurring at all". It carries one recorded sense.
occurring completely or not occurring at all
Definitions, synonyms and semantic relations for all-or-none come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.