WordNet (r) 3.0 (2006):

Zr
    n 1: a lustrous grey strong metallic element resembling
         titanium; it is used in nuclear reactors as a neutron
         absorber; it occurs in baddeleyite but is obtained chiefly
         from zircon [syn: zirconium, Zr, atomic number 40]

The Free On-line Dictionary of Computing (30 December 2018):

zr

    The old country code for Zaire.

   "cd" is now used instead, since Zaire changed its name to
   the Democratic Republic of the Congo.

   (1999-01-27)