yellowness vs wheat

yellowness and wheat both are nouns.

Word	Noun	Adjective	Verb	Adverb
yellowness	Yes	No	No	No
wheat	Yes	No	No	No

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

yellowness: yellow color or pigment; the chromatic color resembling the hue of sunflowers or ripe lemons
wheat: a variable yellow tint; dull yellow, often diluted with white

yellowness (noun)	wheat (noun)
yellow color or pigment; the chromatic color resembling the hue of sunflowers or ripe lemons	a variable yellow tint; dull yellow, often diluted with white
	grains of common wheat; sometimes cooked whole or cracked as cereal; usually ground into flour
	annual or biennial grass having erect flower spikes and light brown grains