Source : WordNet®

barrel cactus
     n 1: a cactus of the genus Ferocactus: unbranched barrel-shaped
          cactus having deep ribs with numerous spines and usually
          large funnel-shaped flowers followed by dry fruits
     2: any cactus of the genus Echinocactus; strongly ribbed and
        very spiny; southwestern United States to Brazil [syn: {echinocactus}]