session vs sitting

session and sitting both are nouns.

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

As nouns, sitting is a hyponym of session; that is, sitting is a word with a more specific, narrower meaning than session:

As nouns, session and sitting are synonyms defined as:

Other synonyms of session include seance.

session (noun)	sitting (noun)
a meeting devoted to a particular activity	the act of assuming or maintaining a seated position
a meeting for execution of a group's functions	(photography) the act of assuming a certain position (as for a photograph or portrait)
a meeting of spiritualists	a session as of a legislature or court
the time during which a school holds classes	a meeting of spiritualists

session (adjective)	sitting (adjective)
	(of persons) having the torso erect and legs bent with the body supported on the buttocks
	not moving and therefore easy to attack