lithium

American  

[lith-ee-uhm] / ˈlɪθ i əm /

noun

1. Chemistry. a soft, silver-white metallic element, the lightest of all metals, occurring combined in certain minerals. Li; 6.939; 3; 0.53 at 20°C.

2. Pharmacology. the substance in its carbonate or citrate form used in the treatment or prophylaxis of bipolar disorder or mania.

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lithium British  

/ ˈlɪθɪəm /

noun

1. 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

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lithium Scientific  

/ lĭth′ē-əm /

1. A soft, silvery metallic element of the alkali group that occurs in small amounts in some minerals. It is the lightest of all metals and is highly reactive. Lithium is used to make alloys, batteries, glass for large telescopes, and ceramics. Atomic number 3; atomic weight 6.941; melting point 179°C; boiling point 1,317°C; specific gravity 0.534; valence 1.

2. See Periodic Table

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Etymology

Origin of lithium

From New Latin, dating back to 1810–20; see origin at lith-, -ium

Explanation

Lithium is a lightweight metal that's commonly used to make batteries. A compound made from this element, also called lithium, is a medication for treating bipolar disorder. Lithium is the lightest and least dense of all the solid elements. It doesn't exist in nature outside of minerals, and it must be extracted in order to be used. In fact, it was named for this quality: the Greek root of lithium is lithos, or "stone." Lithium is used to remove impurities from metals, to make batteries, and in heat-resistant glass, among other things. Lithium salts, or lithium carbonate, can treat the symptoms of some mental illnesses.

Example Sentences

A rail car loaded with lithium batteries caught fire in the Cajon Pass early Wednesday, authorities said.

From Los Angeles Times • Jun. 4, 2026

A survey by the CAA of 1,000 UK passengers in November 2025 suggested more than a third know what lithium batteries are and are aware rules exist, but are unsure what the rules involve.

From BBC • May 25, 2026

Some of the index’s gains have come from areas that don’t get the same attention as big tech — like the materials industry, amid a surge in demand for things like fertilizer and lithium.

From MarketWatch • May 25, 2026

A man caught fire at Melbourne international airport in November 2025 after a lithium power bank in his pocket ignited, leaving him with burns to his leg and fingers.

From BBC • May 24, 2026

The battery was a lithium thionyl chloride non- rechargeable.

From "The Martian" by Andy Weir