lac vs gum-lac

lac and gum-lac both are nouns.

Word	Noun	Adjective	Verb	Adverb
lac	Yes	No	No	No
gum-lac	Yes	No	No	No

As nouns, gum-lac is a hyponym of lac; that is, gum-lac is a word with a more specific, narrower meaning than lac:

lac: resinlike substance secreted by certain lac insects; used in e.g. varnishes and sealing wax
gum-lac: an inferior lac produced by lac insects in Madagascar

Other hyponyms of lac include garnet lac, shellac, stick lac, seed lac.

lac (noun)	gum-lac (noun)
resinlike substance secreted by certain lac insects; used in e.g. varnishes and sealing wax	an inferior lac produced by lac insects in Madagascar