feeding chair vs highchair

feeding chair and highchair both are nouns.

Word	Noun	Adjective	Verb	Adverb
feeding chair	Yes	No	No	No
highchair	Yes	No	No	No

As nouns, feeding chair and highchair are synonyms defined as:

feeding chair and highchair: a chair for feeding a very young child; has four long legs and a footrest and a detachable tray

feeding chair (noun)	highchair (noun)
a chair for feeding a very young child; has four long legs and a footrest and a detachable tray	a chair for feeding a very young child; has four long legs and a footrest and a detachable tray