yttrium
         n 1: a silvery metallic element that is common in rare-earth
               minerals; used in magnesium and aluminum alloys [syn:
               {yttrium}, {Y}, {atomic number 39}]

English Dictionary: yttrium	by the DICT Development Group
From Webster's Revised Unabridged Dictionary (1913) [web1913]:
Yttrium \Yt"tri*um\, n. [NL., from Ytterby, in Sweden. See       {Erbium}.] (Chem.)       A rare metallic element of the boron-aluminium group, found       in gadolinite and other rare minerals, and extracted as a       dark gray powder. Symbol Y. Atomic weight, 89. [Written also       {ittrium}.]          Note: Associated with yttrium are certain rare elements, as                erbium, ytterbium, samarium, etc., which are separated                in a pure state with great difficulty. They are studied                by means of their spark or phosphorescent spectra.                Yttrium is now regarded as probably not a simple                element, but as a mixture of several substances.
From The Elements (22Oct97) [elements]:
yttrium    Symbol: Y    Atomic number: 39    Atomic weight: 88.905    Silvery-grey metallic element of group 3 on the periodic table. Found in    uranium ores. The only natural isotope is Y-89, there are 14 other    artificial isotopes. Chemically resembles the lanthanoids. Stable in the    air below 400 degrees, celsius. Discovered in 1828 by Friedrich Wohler.