from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A fillet of beef covered with pâté de foie gras, encased in pastry, and baked.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A fillet of beef tenderloin coated with pâté de foie gras and a duxelles of mushrooms, wrapped in puff pastry and baked.
Probably from the name Wellington.(American Heritage® Dictionary of the English Language, Fourth Edition)