The American Heritage® Dictionary of the English Language, 4th Edition
n. A very large cactus (Carnegiea gigantea) of the southwest United States and northern Mexico, having ribbed upward-curving branches, white funnel-shaped flowers, and edible red fruit.
n. A large cactus in the genus Carnegiea, native to the Sonoran Desert and characterized by its "arms".
The Century Dictionary and Cyclopedia
n. The giant cactus, Cereus giganteus, a columnar species from 25 to over 50 feet high, growing on stony mesas and low hills in Arizona and adjacent parts of Mexico.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. extremely large treelike cactus of desert regions of southwestern United States having a thick columnar sparsely branched trunk bearing white flowers and edible red pulpy fruit
Word Usage
"The saguaro is a signature plant of the Sonoran Desert."