from The American Heritage® Dictionary of the English Language, 4th Edition
- n. Any of various fleshy, ascomycetous, edible fungi, chiefly of the genus Tuber, that grow underground on or near the roots of trees and are valued as a delicacy.
- n. Any of various chocolate confections, especially one made of a mixture including chopped nuts, rolled into balls and covered with cocoa powder.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. Any of various edible fungi, of the genus Tuber, that grow in the soil in southern Europe; the earthnut.
- n. A creamy chocolate confection, in the form of a ball, covered with cocoa powder.
from the GNU version of the Collaborative International Dictionary of English
- n. Any one of several kinds of roundish, subterranean fungi, usually of a blackish color. The French truffle (Tuber melanosporum) and the English truffle (Tuber æstivum) are much esteemed as articles of food.
from The Century Dictionary and Cyclopedia
- n. A subterranean edible fungus, especially of the ascomycetous genus Tuber.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. edible subterranean fungus of the genus Tuber
- n. creamy chocolate candy
- n. any of various highly prized edible subterranean fungi of the genus Tuber; grow naturally in southwestern Europe
Alteration of French trufe, from Old French, from Old Provençal trufa, from Vulgar Latin *tūfera, truffles, from dialectal variant of Latin tūber, lump.(American Heritage® Dictionary of the English Language, Fourth Edition)
The word in the Germanic languages (except Icelandic) is a loanword from French truffe (previously trufle) (whence Danish and Norwegian trøffel, German Trüffel), which originates from Old Provençal  (Wiktionary)