chairman vs president

chairman and president both are nouns.

Word	Noun	Adjective	Verb	Adverb
chairman	Yes	No	Yes	No
president	Yes	No	No	No

As nouns, president is a hypernym of chairman; that is, president is a word with a broader meaning than chairman:

Other hypernyms of chairman include chair, chairperson, adult female, woman.

chairman (noun)	president (noun)
the male officer who presides at the meetings of an organization	the chief executive of a republic
	an executive officer of a firm or corporation
	the head administrative officer of a college or university
	the officer who presides at the meetings of an organization

chairman (verb)	president (verb)
act or preside as chair, as of an academic department in a university