pentameral Syllabification: (pen·tam·er·al)Pronunciation: /penˈtamərəl/Definition of pentameral adjective Zoology (of symmetry) fivefold, as typical of many echinoderms. Compare with pentamerous.Derivatives pentamerally adverb pentameryPronunciation: /-ˈtamərē/ noun pentameral in other Oxford dictionaries Definition of pentameral in the British & World English dictionary