grinding vs atom

grinding and atom both are nouns.

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

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

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

grinding (noun)	atom (noun)
a harsh and strident sound (as of the grinding of gears)	(physics and chemistry) the smallest component of an element having the chemical properties of the element
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