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
2. A rare element of the carbon-silicon group, intermediate between the metals and nonmetals, obtained from the mineral zircon as a dark sooty powder, or as a gray metallic crystalline substance. Symbol Zr. Atomic weight, 90.4.