office vs office building

office and office building both are nouns.

Word	Noun	Adjective	Verb	Adverb
office	Yes	No	No	No
office building	Yes	No	No	No

office (noun)	office building (noun)
a religious rite or service prescribed by ecclesiastical authorities	a building containing offices where work is done
the actions and activities assigned to or required or expected of a person or group
a job in an organization
place of business where professional or clerical duties are performed
professional or clerical workers in an office
an administrative unit of government
(of a government or government official) holding an office means being in power