Lanthanum
- n. A rare element of the group of the earth metals, allied to aluminium. It occurs in certain rare minerals, as cerite, gadolinite, orthite, etc., and was so named from the difficulty of separating it from cerium, didymium, and other rare elements with which it is usually associated. Atomic weight 138.5. Symbol La.
The word meanings were obtained from OPTED(The Online Plain Text English Dictionary), which is based on “The Project Gutenberg Etext of Webster’s Unabridged Dictionary” which is in turn based on the 1913 US Webster’s Unabridged Dictionary (See Project Gutenburg), as a text file.