vice chairman vs president

vice chairman and president both are nouns.

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

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

Other hypernyms of vice chairman include chair, chairperson.

vice chairman (noun)	president (noun)
one ranking below or serving in the place of a chairman	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