The Collaborative International Dictionary of English v.0.48:

Fuel \Fu"el\, n. [OF. fouail, fuail, or fouaille, fuaille, LL.
   focalium, focale, fr. L. focus hearth, fireplace, in LL.,
   fire. See Focus.] [Formerly written also fewel.]
   1. Any matter used to produce heat by burning; that which
      feeds fire; combustible matter used for fires, as wood,
      coal, peat, etc.
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   2. Anything that serves to feed or increase passion or
      excitement.
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   Artificial fuel, fuel consisting of small particles, as
      coal dust, sawdust, etc., consolidated into lumps or
      blocks.
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The Collaborative International Dictionary of English v.0.48:

Fuel \Fu"el\, v. t.
   1. To feed with fuel. [Obs.]
      [1913 Webster]

            Never, alas I the dreadful name,
            That fuels the infernal flame.        --Cowley.
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   2. To store or furnish with fuel or firing. [Obs.]
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            Well watered and well fueled.         --Sir H.
                                                  Wotton.
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WordNet (r) 3.0 (2006):

fuel
    n 1: a substance that can be consumed to produce energy; "more
         fuel is needed during the winter months"; "they developed
         alternative fuels for aircraft"
    v 1: provide with a combustible substance that provides energy;
         "fuel aircraft, ships, and cars"
    2: provide with fuel; "Oil fires the furnace" [syn: fuel,
       fire]
    3: take in fuel, as of a ship; "The tanker fueled in Bahrain"
    4: stimulate; "fuel the debate on creationism"

Moby Thesaurus II by Grady Ward, 1.0:

54 Moby Thesaurus words for "fuel":
   ammunition, bunker, cater, charge, coal, combustible, detonate,
   encourage, encouragement, exacerbate, excite, exhaust, explode,
   feed, fill up, food, forage, fossil fuel, fuel up, fulminate, gas,
   gas up, incite, incitement, inflame, jet propulsion, kindling,
   liquid oxygen, nourish, nourishment, nuclear fuel, nutriment,
   nutrition, oil, propellant, propulsion charge, provender,
   provision, provocation, provoke, purvey, reaction propulsion,
   refuel, rocket propulsion, sell, stimulate, stimulus, stoke,
   sustain, sustenance, thrust, tinder, top off, victual



Easton's 1897 Bible Dictionary:

Fuel
   Almost every kind of combustible matter was used for fuel, such
   as the withered stalks of herbs (Matt. 6:30), thorns (Ps. 58:9;
   Eccl. 7:6), animal excrements (Ezek. 4:12-15; 15:4, 6; 21:32).
   Wood or charcoal is much used still in all the towns of Syria
   and Egypt. It is largely brought from the region of Hebron to
   Jerusalem. (See COAL.)