rare earth

American  

noun

Chemistry.

1. the oxide of any of the rare-earth elements contained in various minerals.

---

rare earth British  

noun

1. any oxide of a lanthanide

2. Also called: rare-earth element.  another name for lanthanide

---

Etymology

Origin of rare earth

First recorded in 1875–80

Example Sentences

“No one had made a separated heavy rare earth outside of China in 20 years,” said Amanda Lacaze, Lynas’s chief executive.

From The Wall Street Journal • Apr. 26, 2026

Last month, Lynas began producing samarium oxide, a difficult-to-source rare earth in high military demand that is used in heat-resistant magnets for jet fighters and missiles.

From The Wall Street Journal • Apr. 26, 2026

“The Western rare earth sector stands at a critical inflection point, as governments and strategic industries urgently seek reliable sources of critical rare earths — particularly scarce heavy rare earths.”

From MarketWatch • Apr. 20, 2026

Critical Metals Corp. gained 92.5% ownership of Greenland’s Tanbreez rare earth project after government approval.

From Barron's • Apr. 17, 2026

In 1797 Ekeberg showed that gadolinite contained another rare earth, which was given the name yttria.

From Encyclopaedia Britannica, 11th Edition, Volume 9, Slice 7 "Equation" to "Ethics" by Various