Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
closed-ring is an adjective meaning "having atoms linked by bonds represented in circular or triangular form". It carries one recorded sense.
having atoms linked by bonds represented in circular or triangular form
Definitions, synonyms and semantic relations for closed-ring come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.