The Collaborative International Dictionary of English v.0.48:

Pup \Pup\, v. i. [imp. & p. p. Pupped; p. pr. & vb. n.
   Pupping.]
   To bring forth whelps or young, as the female of the canine
   species.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Pup \Pup\, n. [See Puppy.] (Zool.)
   (a) A young dog; a puppy.
   (b) a young seal.
       [1913 Webster]

WordNet (r) 3.0 (2006):

pup
    n 1: young of any of various canines such as a dog or wolf [syn:
         pup, whelp]
    2: an inexperienced young person [syn: puppy, pup]
    v 1: birth; "the dog whelped" [syn: whelp, pup]