Source : Webster's Revised Unabridged Dictionary (1913)

Greaves \Greaves\ (gr[=e]vz), n. pl. [Cf. dial. Sw. grevar
   greaves, LG. greven, G. griebe, also AS. greofa pot. Cf.
   {Gravy.}]
   The sediment of melted tallow. It is made into cakes for
   dogs' food. In Scotland it is called {cracklings}. [Written
   also {graves}.]

Source : WordNet®

cracklings
     n : the crisp residue left after lard has been rendered