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lanthanum

(-nəm)

noun

a soft, malleable, silvery chemical element, one of the rare-earth elements and the first member of the lanthanide series: symbol, La; at. no., 57

Origin: ModL: so named (1839) by G. Mosander (see erbium) < lanthana, lanthanum oxide, lit., the hidden one < Gr lanthanein, to be hidden (see latent): it had previously been undetected in the mineral cerite

See lanthanum in American Heritage Dictionary 4

noun Symbol La

A soft, silvery-white, malleable, ductile, metallic rare-earth element, obtained chiefly from monazite and bastnaesite and used in glass manufacture and with other rare earths in carbon lights for movie and television studio lighting. Atomic number 57; atomic weight 138.91; melting point 920°C; boiling point 3,469°C; specific gravity 5.98 to 6.186; valence 3. See Table at element.

Origin:

Origin: New Latin

Origin: , from Greek lanthanein, to escape notice (from the finding of the element hidden in oxide of cerium)

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