Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
watermelon-shaped is an adjective meaning "having the polar diameter greater than the equatorial diameter". It carries one recorded sense.
having the polar diameter greater than the equatorial diameter
“a prolate spheroid is generated by revolving an ellipse about its major axis”
Definitions, synonyms and semantic relations for watermelon-shaped come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.