Lanthanides and lanthanoids are not the same thing
In "The Love Car Displacement," Dr. Amy Farrah Fowler set all of us straight by explaining that, though the words sound similar, a lanthanide and a lanthanoid are NOT interchangeable. The only correct term for the elements shown at the bottom of every periodic table (because they just don't fit in with those other elements) is "lanthanoid," according to the International Union of Pure and Applied Chemistry. And they would know!
Watch The Big Bang Theory on CBS.