platform vs computer system

platform and computer system both are nouns.

Word	Noun	Adjective	Verb	Adverb
platform	Yes	No	No	No
computer system	Yes	No	No	No

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

platform: the combination of a particular computer and a particular operating system
computer system: a system of one or more computers and associated software with common storage

Other hypernyms of platform include ADP system, ADPS, automatic data processing system, computing system.

platform (noun)	computer system (noun)
a raised horizontal surface	a system of one or more computers and associated software with common storage
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