Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
unmelted is an adjective meaning "not melted". It carries one recorded sense.
not melted
“streets unpassable because of piles of unmelted snow”
Definitions, synonyms and semantic relations for unmelted come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.