The Collaborative International Dictionary of English v.0.48:

ballpoint \ballpoint\ n.
   a pen which has a small metal ball as point of transfer of
   ink to paper, at the tip of a cylandrical and non-refillable
   reservoir of ink; -- short for ballpoint pen.

   Syn: ballpoint pen, ballpen, Biro.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

ballpoint pen
    n 1: a pen that has a small metal ball as the point of transfer
         of ink to paper [syn: ballpoint, ballpoint pen,
         ballpen, Biro]