ZR

n. metallic chemical element (Chemistry)

.zr is the former Internet country code top-level domain (ccTLD) for Zaire. Because Zaire was renamed Democratic Republic of the Congo in 1997, .zr was phased out and .cd took its place. In 2001, .zr was finally terminated.
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Zirconium (IPA: ) is a chemical element that has the symbol Zr and has the atomic number 40. A lustrous, very corrosion resistant, gray-white, strong transition metal that resembles titanium, zirconium is obtained mainly from the mineral zircon. Zirconium is primarily used in nuclear reactors, especially in the cladding of the fuel rods, due to its low neutron-capture cross-section and its resistance to corrosion.
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Noun
1. a lustrous gray 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
(synonym) zirconium, atomic number 40
(hypernym) metallic element, metal
(substance-holonym) baddeleyite

Zr, zirconium, metallic chemical element

n. (also: Zr) zirconium, metallic chemical element, transition metal element