iPod vs stereo system

iPod and stereo system both are nouns.

Word	Noun	Adjective	Verb	Adverb
iPod	Yes	No	No	No
stereo system	Yes	No	No	No

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

iPod: (trademark) a pocket-sized device used to play music files
stereo system: reproducer in which two microphones feed two or more loudspeakers to give a three-dimensional effect to the sound

Other hypernyms of iPod include stereo, stereophonic system, stereophony.

iPod (noun)	stereo system (noun)
(trademark) a pocket-sized device used to play music files	reproducer in which two microphones feed two or more loudspeakers to give a three-dimensional effect to the sound