physicist vs Third Baron Rayleigh

physicist and Third Baron Rayleigh both are nouns.

Word	Noun	Adjective	Verb	Adverb
physicist	Yes	No	No	No
Third Baron Rayleigh	Yes	No	No	No

physicist (noun)	Third Baron Rayleigh (noun)
a scientist trained in physics	English physicist who studied the density of gases and discovered argon; made important contributions to acoustic theory (1842-1919)