potty chair vs stool

potty chair and stool both are nouns.

Word	Noun	Adjective	Verb	Adverb
potty chair	Yes	No	No	No
stool	Yes	No	Yes	No

As nouns, stool is a hypernym of potty chair; that is, stool is a word with a broader meaning than potty chair:

Other hypernyms of potty chair include can, commode, crapper, pot, potty, throne, toilet.

potty chair (noun)	stool (noun)
toilet consisting of a small seat used by young children	a simple seat without a back or arms
	a plumbing fixture for defecation and urination
	(forestry) the stump of a tree that has been felled or headed for the production of saplings
	solid excretory product evacuated from the bowels

potty chair (verb)	stool (verb)
	have a bowel movement
	grow shoots in the form of stools or tillers
	react to a decoy, of wildfowl
	lure with a stool, as of wild fowl