outside vs open

outside and open both are nouns.

Word	Noun	Adjective	Verb	Adverb
outside	Yes	Yes	No	Yes
open	Yes	Yes	Yes	No

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

Other hyponyms of outside include open air, out-of-doors, outdoors.

outside (noun)	open (noun)
the outer side or surface of something	information that has become public
the region that is outside of something	a tournament in which both professionals and amateurs may play
	a clear or unobstructed space or expanse of land or water
	where the air is unconfined

outside (adjective)	open (adjective)
relating to or being on or near the outer side or limit	ready or willing to receive favorably
located, suited for, or taking place in the open air	affording unobstructed entrance and exit; not shut or closed
leading to or from the outside	affording free passage or access
originating or belonging beyond some bounds	(set theory) of an interval that contains neither of its endpoints
functioning outside the boundaries or precincts of an organized unit	open and observable; not secret or hidden
coming from the outside	used of mouth or eyes
from or between other countries	ready for business
(of a baseball pitch) on the far side of home plate from the batter	not having been filled
on or toward an outer edge	(of textures) full of small openings or gaps
unlikely to occur	openly straightforward and direct without reserve or secretiveness
	not requiring union membership
	open to or in view of all
	possibly accepting or permitting
	without undue constriction as from e.g. tenseness or inhibition
	having no protecting cover or enclosure
	affording free passage or view
	with no protection or shield
	accessible to all
	not sealed or having been unsealed
	not brought to a conclusion; subject to further thought
	not defended or capable of being defended

outside (verb)	open (verb)
	make available
	become available
	make the opening move
	cause to open or to become open
	become open
	spread out or open from a closed or folded state
	display the contents of a file or start an application as on a computer
	afford access to
	start to operate or function or cause to start operating or functioning
	begin or set in action, of meetings, speeches, recitals, etc.
	have an opening or passage or outlet

outside (adverb)	open (adverb)
outside a building
on the outside