executive session vs session

executive session and session both are nouns.

Word	Noun	Adjective	Verb	Adverb
executive session	Yes	No	No	No
session	Yes	No	No	No

As nouns, session is a hypernym of executive session; that is, session is a word with a broader meaning than executive session:

executive session: a session (usually of a legislative body) that is closed to the public
session: a meeting for execution of a group's functions

executive session (noun)	session (noun)
a session (usually of a legislative body) that is closed to the public	a meeting devoted to a particular activity
	a meeting for execution of a group's functions
	a meeting of spiritualists
	the time during which a school holds classes