water buffalo

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

• noun A large, domesticated buffalo (Bubalus bubalis) of Asia that has large spreading horns and is used especially as a draft animal. The wild water buffalo is sometimes described as a different species, B. arnee.

from The Century Dictionary.

• noun See watercow.

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

• (Zoöl.) The European buffalo.

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

• noun A large ungulate, widely used as a domestic animal in Asia, South America. North Africa and Europe.
• noun US, colloquial A water tank mounted on a trailer to be towed by a motor vehicle.

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

• noun an Asian buffalo that is often domesticated for use as a draft animal