palliasse vs mattress

palliasse and mattress both are nouns.

Word	Noun	Adjective	Verb	Adverb
palliasse	Yes	No	No	No
mattress	Yes	No	No	No

As nouns, mattress is a hypernym of palliasse; that is, mattress is a word with a broader meaning than palliasse:

palliasse: mattress consisting of a thin pad filled with straw or sawdust
mattress: a large thick pad filled with resilient material and often incorporating coiled springs, used as a bed or part of a bed

palliasse (noun)	mattress (noun)
mattress consisting of a thin pad filled with straw or sawdust	a large thick pad filled with resilient material and often incorporating coiled springs, used as a bed or part of a bed