A proportion used in determining the dimensional relationship of a representation to that which it represents: a world map with a scale of 1:4,560,000. b. A calibrated line, as on a map or an architectural plan, indicating such a proportion.
Yttria (yttrium oxide, Y 2 O 3), was discovered by Johann Gadolin in 1794 in a mineral called gadolinite from Ytterby. Ytterby is the site of a quarry in Sweden which contains many unusual minerals containing erbium, terbium, and ytterbium as well as yttrium.
Yttrium (Y, element 39; emits red light) Yttrium oxide glass is heat- and shockresistant, and used for camera lenses. Yttrium is used in superconductors, which can conduct electricity without any loss of energy; and yttrium aluminium garnet is used in lasers and makes sparkling diamond-like gems.