- a soft, silver-white metallic element, the lightest of all metals, occurring combined in certain minerals. Symbol: Li; atomic weight: 6.939; atomic number: 3; specific gravity: 0.53 at 20°C.
- the substance in its carbonate or citrate form used in the treatment or prophylaxis of bipolar disorder or mania.
- a soft silvery element of the alkali metal series: the lightest known metal, used as an alloy hardener, as a reducing agent, and in batteries. Symbol: Li; atomic no: 3; atomic wt: 6.941; valency: 1; relative density: 0.534; melting pt: 180.6°C; boiling pt: 1342°C
