transition metal
(also transition element)
Definition of transition metal
noun
Chemistry- any of the set of metallic elements occupying a central block (Groups IVB-VIII, IB, and IIB, or 4-12) in the periodic table, e.g. iron, manganese, chromium, and copper. Chemically they show variable valency and a strong tendency to form coordination compounds, and many of their compounds are coloured.