taste bud

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

• noun Any of numerous spherical or ovoid clusters of receptor cells found mainly in the epithelium of the tongue and constituting the end organs of the sense of taste.

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

• noun Alternative form of tastebud.

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

• noun an oval sensory end organ on the surface of the tongue