periodical vs serial

periodical and serial both are nouns.

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

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

Other hyponyms of periodical include digest, pictorial, serial publication, series, organ, issue, number, journal, review.

periodical (noun)	serial (noun)
a publication that appears at fixed intervals	a serialized set of programs
	a periodical that appears at scheduled times

periodical (adjective)	serial (adjective)
happening or recurring at regular intervals	pertaining to or occurring in or producing a series
	pertaining to or composed in serial technique
	of or relating to the sequential performance of multiple operations
	in regular succession without gaps