android vs operating system

android and operating system both are nouns.

Word	Noun	Adjective	Verb	Adverb
android	Yes	No	No	No
operating system	Yes	No	No	No

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

android: An operating system from Google for mobile devices
operating system: (computer science) software that controls the execution of computer programs and may provide various services

Other hypernyms of android include OS.

android (noun)	operating system (noun)
an automaton that resembles a human being	(computer science) software that controls the execution of computer programs and may provide various services
An operating system from Google for mobile devices