outdoor stage vs platform

outdoor stage and platform both are nouns.

Word	Noun	Adjective	Verb	Adverb
outdoor stage	Yes	No	No	No
platform	Yes	No	No	No

As nouns, platform is a hypernym of outdoor stage; that is, platform is a word with a broader meaning than outdoor stage:

outdoor stage (noun)	platform (noun)
a platform where a (brass) band can play in the open air	a raised horizontal surface
	any military structure or vehicle bearing weapons
	a woman's shoe with a very high thick sole
	the combination of a particular computer and a particular operating system
	a long, flat raised structure of a railway station, where people get on and off of trains
	a document stating the aims and principles of a political party