installation vs installment

installation and installment both are nouns.

Word	Noun	Adjective	Verb	Adverb
installation	Yes	No	No	No
installment	Yes	No	No	No

As nouns, installation and installment are synonyms defined as:

installation and installment: the act of installing something (as equipment)

Other synonyms of installation include installing, instalment.

installation (noun)	installment (noun)
the act of installing something (as equipment)	the act of installing something (as equipment)
a building or place that provides a particular service or is used for a particular industry	a part of a broadcast serial
a formal entry into an organization or position or office	a part of a published serial
	a payment of part of a debt; usually paid at regular intervals