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.
      [1913 Webster]

   2. Anything that serves to feed or increase passion or
      excitement.
      [1913 Webster]

   Artificial fuel, fuel consisting of small particles, as
      coal dust, sawdust, etc., consolidated into lumps or
      blocks.
      [1913 Webster]