The Collaborative International Dictionary of English v.0.48:

Cud \Cud\ (k[u^]d), n. [AS. cudu, cwudu,cwidu,cweodo, of
   uncertain origin; cf, G. k["o]der bait, Icel. kvi[eth]r womb,
   Goth. qi[thorn]us. Cf. Quid.]
   1. That portion of food which is brought up into the mouth by
      ruminating animals from their first stomach, to be chewed
      a second time.
      [1913 Webster]

            Whatsoever parteth the hoof, and is cloven-footed,
            and cheweth the cud, among the beasts, that shall ye
            eat.                                  --Levit. xi. 3
      [1913 Webster]

   2. A portion of tobacco held in the mouth and chewed; a quid.
      [Low]
      [1913 Webster]

   3. The first stomach of ruminating beasts. --Crabb.
      [1913 Webster]

   To chew the cud, to ruminate; to meditate; used with of;
      as, to chew the cud of bitter memories.
      [1913 Webster]

            Chewed the thrice turned cud of wrath. --Tennyson.
      [1913 Webster]

WordNet (r) 3.0 (2006):

cud
    n 1: food of a ruminant regurgitated to be chewed again [syn:
         cud, rechewed food]
    2: a wad of something chewable as tobacco [syn: chew, chaw,
       cud, quid, plug, wad]

Moby Thesaurus II by Grady Ward, 1.0:

26 Moby Thesaurus words for "cud":
   bite, bolus, cavendish, champ, chaw, chew, chewing tobacco, chomp,
   cut plug, eating tobacco, fid, gnash, gob, morsel, mouthful, munch,
   navy, navy plug, nibble, nip, pigtail, quid, snap, swallow,
   tobacco juice, twist



V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

CUD
       Color Universal Design (Eizo, LCD)