wall painting vs fresco

wall painting and fresco both are nouns.

Word	Noun	Adjective	Verb	Adverb
wall painting	Yes	No	No	No
fresco	Yes	No	Yes	No

As nouns, fresco is a hyponym of wall painting; that is, fresco is a word with a more specific, narrower meaning than wall painting:

wall painting (noun)	fresco (noun)
a painting that is applied to a wall surface	a durable method of painting on a wall by using watercolors on wet plaster
	a mural done with watercolors on wet plaster

wall painting (verb)	fresco (verb)
	paint onto wet plaster on a wall