serial vs monthly

serial and monthly both are nouns.

Word	Noun	Adjective	Verb	Adverb
serial	Yes	Yes	No	No
monthly	Yes	Yes	No	Yes

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

Other hyponyms of serial include semiweekly, weekly, semimonthly, quarterly, bimonthly, biweekly.

serial (noun)	monthly (noun)
a serialized set of programs	a periodical that is published every month (or 12 issues per year)
a periodical that appears at scheduled times

serial (adjective)	monthly (adjective)
pertaining to or occurring in or producing a series	of or occurring or payable every month
pertaining to or composed in serial technique
of or relating to the sequential performance of multiple operations
in regular succession without gaps

serial (adverb)	monthly (adverb)
	occurring once a month