paillasse vs mattress

paillasse and mattress both are nouns.

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

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

paillasse: 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

paillasse (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