1. Something consumed to produce energy, especially:
a. A material such as wood, coal, gas, or oil burned to produce heat or power.
b. Fissionable material used in a nuclear reactor.
c. Nutritive material metabolized by a living organism; food.
2. Something that maintains or stimulates an activity or emotion: "Money is the fuel of a volunteer organization" (Natalie de Combray).
v. fu·eled, fu·el·ing, fu·els also fu·elled or fu·el·ling
1. To provide with fuel.
2. To support or stimulate the activity or existence of: rhetoric that fueled the dissenters.
To take in fuel.
[Middle English feuel, from Old French fouaille, feuaile, from Vulgar Latin *focālia, neuter pl. of *focālis, of the hearth or fireplace, from Latin focus, hearth, fireplace.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2020 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.