girasol vs opal

girasol and opal both are nouns.

Word	Noun	Adjective	Verb	Adverb
girasol	Yes	No	No	No
opal	Yes	No	No	No

As nouns, opal is a hypernym of girasol; that is, opal is a word with a broader meaning than girasol:

girasol: an opal with flaming orange and yellow and red colors
opal: a translucent mineral consisting of hydrated silica of variable color; some varieties are used as gemstones

girasol (noun)	opal (noun)
tall perennial with hairy stems and leaves; widely cultivated for its large irregular edible tubers	a translucent mineral consisting of hydrated silica of variable color; some varieties are used as gemstones
an opal with flaming orange and yellow and red colors