Source : Webster's Revised Unabridged Dictionary (1913)

Manna croup \Man"na croup`\ [Manna + Russ. & Pol. krupa groats,
   grits.]
   1. The portions of hard wheat kernels not ground into flour
      by the millstones: a kind of semolina prepared in Russia
      and used for puddings, soups, etc. -- called also {manna
      groats}.

   2. The husked grains of manna grass.