black locust

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

• noun A deciduous tree (Robinia pseudoacacia) of the pea family, native chiefly to the southeast United States but widely naturalized, having pinnately compound leaves, hanging clusters of fragrant, creamy-white flowers, flat brown pods, and strong wood.

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

• noun A tree, Robinia pseudoacacia, in the subfamily Faboideae of the pea family Fabaceae, native to the southeastern United States, but widely planted and naturalized elsewhere in temperate North America, Europe and Asia; considered an invasive species in some areas.

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

• noun strong stiff wood of a black-locust tree; very resistant to decay
• noun large thorny tree of eastern and central United States having pinnately compound leaves and drooping racemes of white flowers; widely naturalized in many varieties in temperate regions