gypsum vs gesso

gypsum and gesso both are nouns.

Word	Noun	Adjective	Verb	Adverb
gypsum	Yes	No	No	No
gesso	Yes	No	No	No

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

gypsum: a common white or colorless mineral (hydrated calcium sulphate) used to make cements and plasters (especially plaster of Paris)
gesso: gypsum or plaster of Paris spread on a surface to make it suitable for painting or gilding (or a surface so prepared)

Other hyponyms of gypsum include alabaster, terra alba.

gypsum (noun)	gesso (noun)
a common white or colorless mineral (hydrated calcium sulphate) used to make cements and plasters (especially plaster of Paris)	gypsum or plaster of Paris spread on a surface to make it suitable for painting or gilding (or a surface so prepared)