signboard vs shingle

signboard and shingle both are nouns.

Word	Noun	Adjective	Verb	Adverb
signboard	Yes	No	No	No
shingle	Yes	No	Yes	No

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

signboard: structure displaying a board on which advertisements can be posted
shingle: a small signboard outside the office of a lawyer or doctor, e.g.

Other hyponyms of signboard include billboard, hoarding, sandwich board, scoreboard.

signboard (noun)	shingle (noun)
structure displaying a board on which advertisements can be posted	a small signboard outside the office of a lawyer or doctor, e.g.
	building material used as siding or roofing
	coarse beach gravel of small waterworn stones and pebbles (or a stretch of shore covered with such gravel)

signboard (verb)	shingle (verb)
	cover with shingles