cnidarian Cnidaria • Cnidian · · · Info · Definitions · Synonyms · Characters · · cnidarian · · Text Latin · · Script 9 · · Length 4 · · Syllables Definitions · · · (noun) radially symmetrical animals having saclike bodies with only one opening and tentacles with stinging structures; they occur in polyp and medusa forms. Synonyms: coelenterate. · · Noun Definition 1 Synonyms · · · coelenterate · · Synonym 1 Characters · · a latin small letter a U+0061 c latin small letter c U+0063 d latin small letter d U+0064 i latin small letter i U+0069 n latin small letter n U+006E r latin small letter r U+0072