porter vs redcap

porter and redcap both are nouns.

Word	Noun	Adjective	Verb	Adverb
porter	Yes	No	Yes	No
redcap	Yes	No	No	No

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

porter: a person employed to carry luggage and supplies
redcap: a porter who helps passengers with their baggage at a railroad station

Other hyponyms of porter include skycap.

porter (noun)	redcap (noun)
a very dark sweet ale brewed from roasted unmalted barley	a porter who helps passengers with their baggage at a railroad station
a person employed to carry luggage and supplies	a member of the military police in Britain
a railroad employee who assists passengers (especially on sleeping cars)
someone who guards an entrance

porter (verb)	redcap (verb)
carry luggage or supplies