tannia n tropical American aroid having edible tubers that are cooked and eaten like yams or potatoes Usage(s) Stunned by the tariff, which cuts their exports to Britain, officials of the six other EFTA nations revived the bitter chant: "Bri tannia waives the rules. Synonym(s) yautia spoonflower malanga Xanthosoma sagittifolium Xanthosoma atrovirens