potluck vs meal

potluck and meal both are nouns.

Word	Noun	Adjective	Verb	Adverb
potluck	Yes	No	No	No
meal	Yes	No	No	No

As nouns, meal is a hypernym of potluck; that is, meal is a word with a broader meaning than potluck:

potluck: whatever happens to be available especially when offered to an unexpected guest or when brought by guests and shared by all
meal: the food served and eaten at one time

Other hypernyms of potluck include repast.

potluck (noun)	meal (noun)
whatever happens to be available especially when offered to an unexpected guest or when brought by guests and shared by all	the food served and eaten at one time
	coarsely ground foodstuff; especially seeds of various cereal grasses or pulse
	any of the occasions for eating food that occur by custom or habit at more or less fixed times