Source : Webster's Revised Unabridged Dictionary (1913)

Gravel \Grav"el\, n. [OF. gravele, akin to F. gr?ve a sandy
   shore, strand; of Celtic origin; cf. Armor. grouan gravel, W.
   gro coarse gravel, pebbles, and Skr. gr[=a]van stone.]
   1. Small stones, or fragments of stone; very small pebbles,
      often intermixed with particles of sand.

   2. (Med.) A deposit of small calculous concretions in the
      kidneys and the urinary or gall bladder; also, the disease
      of which they are a symptom.

   {Gravel powder}, a coarse gunpowder; pebble powder.