shellack vs shellac

shellack is not a noun while shellac is a noun.

Word	Noun	Adjective	Verb	Adverb
shellack	No	No	Yes	No
shellac	Yes	No	Yes	No

As verbs, shellack and shellac are synonyms defined as:

shellack (noun)	shellac (noun)
	a thin varnish made by dissolving lac in ethanol; used to finish wood
	lac purified by heating and filtering; usually in thin orange or yellow flakes but sometimes bleached white

shellack (verb)	shellac (verb)
cover with shellac	cover with shellac