Meaning of transition element

transi'tion el"ement

Pronunciation: [key]
— Chem. Chem.
  1. any element in any of the series of elements with atomic numbers 21–29, 39–47, 57–79, and 89–107, that in a given inner orbital has less than a full quota of electrons. Also called transi&prim;tion met&sec;al.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.