instalment vs episode

instalment and episode both are nouns.

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

As nouns, instalment and episode are synonyms defined as:

Other synonyms of instalment include installment.

instalment (noun)	episode (noun)
the act of installing something (as equipment)	film consisting of a succession of related shots that develop a given subject in a movie
a part of a broadcast serial	a part of a broadcast serial
a part of a published serial	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