lunchroom vs eating place

lunchroom and eating place both are nouns.

Word	Noun	Adjective	Verb	Adverb
lunchroom	Yes	No	No	No
eating place	Yes	No	No	No

As nouns, eating place is a hypernym of lunchroom; that is, eating place is a word with a broader meaning than lunchroom:

Other hypernyms of lunchroom include eatery, eating house, restaurant.

lunchroom (noun)	eating place (noun)
a restaurant (in a facility) where lunch can be purchased	a building where people go to eat