prop vs bolster

prop and bolster both are nouns.

Word	Noun	Adjective	Verb	Adverb
prop	Yes	No	Yes	No
bolster	Yes	No	Yes	No

As verbs, bolster is a hyponym of prop; that is, bolster is a word with a more specific, narrower meaning than prop:

prop (noun)	bolster (noun)
a support placed beneath or against something to keep it from shaking or falling	a pillow that is often put across a bed underneath the regular pillows
a propeller that rotates to push against air
any movable articles or objects used on the set of a play or movie

prop (verb)	bolster (verb)
support by placing against something solid or rigid	add padding to
	support and strengthen
	prop up with a pillow or bolster