Lanthanoids.

Explanation

The series of fourteen elements from `._(58)Ce` to `._(71)Lu` in which a differentiating electron enters 4f sub-shell and follows lanthanum is called lanthanoid series and the elements are called lanthanoids.
Their general electronic configuration is `[Xe]overset(1-14)(4f)overset(0-1)(5d)" "6s^(2)`.