highchair vs feeding chair

highchair and feeding chair both are nouns.

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

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

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

highchair (noun)	feeding chair (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