Main Entry: lith·i·um

Pronunciation: \ˈli-thē-əm\

Function: noun

Etymology: New Latin, from lithia oxide of lithium, from Greek lithos

Date: 1818

1 : a soft silver-white element of the alkali metal group that is the lightest metal known and that is used especially in alloys and glass, in chemical synthesis, and in storage batteries — see element table
2 : a salt of lithium (as lithium carbonate) used in psychiatric medicine