monad vs atom

monad and atom both are nouns.

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

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

monad: (chemistry) an atom having a valence of one
atom: (physics and chemistry) the smallest component of an element having the chemical properties of the element

monad (noun)	atom (noun)
(biology) a single-celled microorganism (especially a flagellate protozoan)	(physics and chemistry) the smallest component of an element having the chemical properties of the element
a singular metaphysical entity from which material properties are said to derive	(nontechnical usage) a tiny piece of anything
(chemistry) an atom having a valence of one