fuel

Etymology

From Middle English fewell, from Old French fouaille, feuaille (“firewood, kindling”), from feu (“fire”), from Late Latin focus (“fire”), from Latin focus (“hearth”). Cognate with Spanish fuego (“fire”), and Portuguese fogo (“fire”). Doublet of focus.

noun

1. Substance consumed to provide energy through combustion, or through chemical or nuclear reaction.
   More than a mere source of Promethean sustenance to thwart the cold and cook one's meat, wood was quite simply mankind's first industrial and manufacturing fuel. 2006, Edwin Black, chapter 2, in Internal Combustion
2. Substance that provides nourishment for a living organism; food.
3. (figurative) Something that stimulates, encourages or maintains an action.
   His books were fuel for the revolution.
   Money is the fuel for economy.
   That film was nightmare fuel!
   Small arms ammunition is the fuel that keeps many of the world’s conflicts raging. June 15, 2006, “Ammunition: the fuel of conflict”, in Oxfam International

verb

1. To provide with fuel.
   The workings now employ ten twin-units, which are fuelled at Hornsey but return to Cambridge diesel depot for their weekly maintenance; …. 1959 May, “Talking of Trains: By diesel m.u. to Moorgate”, in Trains Illustrated, page 235
2. To exacerbate, to cause to grow or become greater.