grinding vs molecule

grinding and molecule both are nouns.

Word	Noun	Adjective	Verb	Adverb
grinding	Yes	No	No	No
molecule	Yes	No	No	No

As nouns, molecule is a hypernym of grinding; that is, molecule is a word with a broader meaning than grinding:

Other hypernyms of grinding include atom, corpuscle, mote, particle, speck.

grinding (noun)	molecule (noun)
a harsh and strident sound (as of the grinding of gears)	(physics and chemistry) the simplest structural unit of an element or compound
material resulting from the process of grinding	(nontechnical usage) a tiny piece of anything
the wearing down of rock particles by friction due to water or wind or ice