jam box vs stereo system

jam box and stereo system both are nouns.

Word	Noun	Adjective	Verb	Adverb
jam box	Yes	No	No	No
stereo system	Yes	No	No	No

As nouns, stereo system is a hypernym of jam box; that is, stereo system is a word with a broader meaning than jam box:

jam box: a portable stereo
stereo system: reproducer in which two microphones feed two or more loudspeakers to give a three-dimensional effect to the sound

Other hypernyms of jam box include stereo, stereophonic system, stereophony.

jam box (noun)	stereo system (noun)
a portable stereo	reproducer in which two microphones feed two or more loudspeakers to give a three-dimensional effect to the sound