squab vs poultry

squab and poultry both are nouns.

Word	Noun	Adjective	Verb	Adverb
squab	Yes	Yes	No	No
poultry	Yes	No	No	No

As nouns, poultry is a hypernym of squab; that is, poultry is a word with a broader meaning than squab:

squab: flesh of a pigeon suitable for roasting or braising; flesh of a dove (young squab) may be broiled
poultry: flesh of chickens or turkeys or ducks or geese raised for food

squab (noun)	poultry (noun)
an unfledged pigeon	a domesticated gallinaceous bird thought to be descended from the red jungle fowl
a soft padded sofa	flesh of chickens or turkeys or ducks or geese raised for food
flesh of a pigeon suitable for roasting or braising; flesh of a dove (young squab) may be broiled

squab (adjective)	poultry (adjective)
short and fat