9 letters · 12 points in Scrabble
noun radially symmetrical animals having saclike bodies with only one opening and tentacles with stinging structures; they occur in polyp and medusa forms
originFrom translingual Cnidaria + -an, derived from New Latin Cnīdāria, derived from Ancient Greek κνῑ́δη (knī́dē, “sea nettle”).
Etymology from Wiktionary, CC BY-SA 3.0