First Duke of Wellington vs Iron Duke

First Duke of Wellington and Iron Duke both are nouns.

Word	Noun	Adjective	Verb	Adverb
First Duke of Wellington	Yes	No	No	No
Iron Duke	Yes	No	No	No

As nouns, First Duke of Wellington and Iron Duke are synonyms defined as:

First Duke of Wellington and Iron Duke: British general and statesman; he defeated Napoleon at Waterloo; subsequently served as Prime Minister (1769-1852)

Other synonyms of First Duke of Wellington include Arthur Wellesley, Duke of Wellington, Wellington.

First Duke of Wellington (noun)	Iron Duke (noun)
British general and statesman; he defeated Napoleon at Waterloo; subsequently served as Prime Minister (1769-1852)	British general and statesman; he defeated Napoleon at Waterloo; subsequently served as Prime Minister (1769-1852)