1. [n]  young of any of various canines such as a dog or wolf
2. [n]  an inexperienced young person
3. [v]  birth; of dogs

PUP is a 3 letter word that starts with P.

1. \Pup\, n. [See {Puppy}.] (Zo["o]l.)
   (a) A young dog; a puppy.
   (b) a young seal.
   
   
   
   

2. \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.