mattress vs pallet

mattress and pallet both are nouns.

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

As nouns, pallet is a hyponym of mattress; that is, pallet is a word with a more specific, narrower meaning than mattress:

mattress: a large thick pad filled with resilient material and often incorporating coiled springs, used as a bed or part of a bed
pallet: a mattress filled with straw or a pad made of quilts; used as a bed

Other hyponyms of mattress include air mattress, feather bed, featherbed, futon, paillasse, palliasse, spring mattress, tick.

mattress (noun)	pallet (noun)
a large thick pad filled with resilient material and often incorporating coiled springs, used as a bed or part of a bed	a mattress filled with straw or a pad made of quilts; used as a bed
	board that provides a flat surface on which artists mix paints and the range of colors used
	a hand tool with a flat blade used by potters for mixing and shaping clay
	a portable platform for storing or moving goods that are stacked on it
	the range of colour characteristic of a particular artist or painting or school of art