The Collaborative International Dictionary of English v.0.48:

Gravy \Gra"vy\, n.; pl. Gravies. [OE. greavie; prob. fr.
   greaves, graves, the sediment of melted tallow. See
   Greaves.]
   1. The juice or other liquid matter that drips from flesh in
      cooking, made into a dressing for the food when served up.
      [1913 Webster]

   2. Liquid dressing for meat, fish, vegetables, etc.
      [1913 Webster]