rare earth
Concise Oxford English Dictionary © 2008 Oxford University Press:
rare earth (also rare-earth element or metal)
▶noun Chemistry any of a group of chemically similar metallic elements comprising the lanthanide series and (usually) scandium and yttrium.
'rare earth' also found in these Oxford entries:
allanite
- didymium
- lanthanide
- lanthanum
- misch metal
- monazite
- scandium
- ytterbium
- yttrium
