fuel (n.) Look up fuel at Dictionary.com
early 14c., from Old French foaile "bundle of firewood," from Vulgar Latin legal term *focalia "right to demand material for making fire," neuter plural of Latin focalis "pertaining to a hearth," from focus "hearth" (see focus (n.)). Figurative use from 1570s.
fuel (v.) Look up fuel at Dictionary.com
1590s, from fuel (n.). Related: Fueled; fueling.