noun. any element of the lanthanide series (atomic numbers 57 through 71).
- rare earth
- rare-earth element
- terbium metal
Sentences with lanthanide
SmCo and NdFeB magnets are called "rare earth" because they are made from the rare earth, or lanthanide series, of the periodic table of elements, according to Magnet Man.
2. Noun, singular or mass
The lanthanide and actinide make up the f-orbitals.