boob tube vs receiving system

boob tube and receiving system both are nouns.

Word	Noun	Adjective	Verb	Adverb
boob tube	Yes	No	No	No
receiving system	Yes	No	No	No

As nouns, receiving system is a hypernym of boob tube; that is, receiving system is a word with a broader meaning than boob tube:

boob tube: an electronic device that receives television signals and displays them on a screen
receiving system: set that receives radio or tv signals

Other hypernyms of boob tube include receiver.

boob tube (noun)	receiving system (noun)
an electronic device that receives television signals and displays them on a screen	set that receives radio or tv signals