loaf sugar

from WordNet (r) 3.0 (2006)

loaf sugar
    n 1: a large conical loaf of concentrated refined sugar [syn:
         {sugarloaf}, {sugar loaf}, {loaf sugar}]

from The Collaborative International Dictionary of English v.0.48

Loaf \Loaf\, n.; pl. {Loaves}. [OE. lof, laf, AS. hl[=a]f; akin
   to G. laib, OHG. hleip, Icel. hleifr, Goth. hlaifs, Russ.
   khlieb', Lith. kl["e]pas. Cf. {Lady}, {Lammas}, {Lord}.]
   Any thick lump, mass, or cake; especially, a large regularly
   shaped or molded mass, as of bread, sugar, or cake. --Bacon.
   [1913 Webster]

   {Loaf sugar}, refined sugar that has been formed into a
      conical loaf in a mold.
      [1913 Webster]