The Collaborative International Dictionary of English v.0.48:

Quid \Quid\, n. [See Cud.]
   A portion suitable to be chewed; a cud; as, a quid of
   tobacco.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Quid \Quid\ (kw[i^]d), n.; pl. quid. [Etym. uncertain.]
   An English coin, a sovereign. [Slang, Eng.]
   [Webster 1913 Suppl. +PJC]

         They invited him to come to-morrow, . . . and bring
         half a quid with him.                    --Charles
                                                  Reade.
   [Webster 1913 Suppl.]

The Collaborative International Dictionary of English v.0.48:

Quid \Quid\, v. t. (Man.)
   To drop from the mouth, as food when partially chewed; --
   said of horses. --Youatt.
   [1913 Webster]

WordNet (r) 3.0 (2006):

quid
    n 1: the basic unit of money in Great Britain and Northern
         Ireland; equal to 100 pence [syn: British pound, pound,
         British pound sterling, pound sterling, quid]
    2: something for something; that which a party receives (or is
       promised) in return for something he does or gives or
       promises [syn: quid pro quo, quid]
    3: a wad of something chewable as tobacco [syn: chew, chaw,
       cud, quid, plug, wad]