The Collaborative International Dictionary of English v.0.48:

Biro \Biro\ n. [from the name of the inventor.]
   a pen with small metal ball as point of transfer of ink to
   paper; same as ballpoint pen.

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

WordNet (r) 3.0 (2006):

Biro
    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]