simple sugar vs tetrose

simple sugar and tetrose both are nouns.

Word	Noun	Adjective	Verb	Adverb
simple sugar	Yes	No	No	No
tetrose	Yes	No	No	No

As nouns, tetrose is a hyponym of simple sugar; that is, tetrose is a word with a more specific, narrower meaning than simple sugar:

simple sugar: a sugar (like sucrose or fructose) that does not hydrolyse to give other sugars; the simplest group of carbohydrates
tetrose: any monosaccharide sugar containing four atoms of carbon per molecule

Other hyponyms of simple sugar include triose, pentose, hexose, aldose, ketose, heptose.

simple sugar (noun)	tetrose (noun)
a sugar (like sucrose or fructose) that does not hydrolyse to give other sugars; the simplest group of carbohydrates	any monosaccharide sugar containing four atoms of carbon per molecule