noun Download 🔗Share Any of the 14 rare earth elements from cerium (or from lanthanum) to lutetium in the periodic table; because their outermost orbitals are empty, they have very similar chemistry; below them are the actinides. Examples : "Many modern electronics rely on lanthanides, like neodymium, to create powerful magnets used in speakers and hard drives. " element chemistry Chat with AIVocabulary GamePractice Reading