Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
highly-developed is an adjective meaning "(used of societies) having high industrial development". It carries one recorded sense.
(used of societies) having high industrial development
“developed countries”
Definitions, synonyms and semantic relations for highly-developed come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.