episode vs cliffhanger

episode and cliffhanger both are nouns.

Word	Noun	Adjective	Verb	Adverb
episode	Yes	No	No	No
cliffhanger	Yes	No	No	No

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

episode (noun)	cliffhanger (noun)
film consisting of a succession of related shots that develop a given subject in a movie	an episode that ends in suspense
a part of a broadcast serial	a contest whose outcome is uncertain up to the very end
a brief section of a literary or dramatic work that forms part of a connected series
a happening that is distinctive in a series of related events