barrel cactus

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Any of various cacti in the genera Ferocactus and Echinocactus, having ribbed spiny unbranched stems that are globular to columnar in shape.

from The Century Dictionary.

• noun The bisnaga, Echinocactus: so named from its form and size. See Echinocactus and visnaga.

from the GNU version of the Collaborative International Dictionary of English.

• noun any of several large cacti native to the southwestern U. S. and Mexico, having a short cylindrical form with deep vertical ribs and bearing sharp spines. They are classed in the genera Ferocactus and Echinocactus.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun Any cactus with an approximately barrel-like shape.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun 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
• noun any cactus of the genus Echinocactus; strongly ribbed and very spiny; southwestern United States to Brazil