porch vs portico

porch and portico both are nouns.

Word	Noun	Adjective	Verb	Adverb
porch	Yes	No	No	No
portico	Yes	No	No	No

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

porch: a structure attached to the exterior of a building often forming a covered entrance
portico: a porch or entrance to a building consisting of a covered and often columned area

Other hyponyms of porch include back porch, deck, front porch, stoep, stoop, gallery, veranda, verandah.

porch (noun)	portico (noun)
a structure attached to the exterior of a building often forming a covered entrance	a porch or entrance to a building consisting of a covered and often columned area