Main Entry: lan·tha·nide

Pronunciation: \ˈlan(t)-thə-ˌnīd\

Variant(s): also lan·tha·noid \-ˌnȯid\

Function: noun

Etymology: International Scientific Vocabulary

Date: 1926

: any of the series of elements with increasing atomic numbers that begins with lanthanum or cerium and ends with lutetium — see periodic table table