word processing system vs word processor

word processing system and word processor both are nouns.

Word	Noun	Adjective	Verb	Adverb
word processing system	Yes	No	No	No
word processor	Yes	No	No	No

As nouns, word processing system and word processor are synonyms defined as:

word processing system and word processor: an application that provides the user with tools needed to write and edit and format text and to send it to a printer

word processing system (noun)	word processor (noun)
an application that provides the user with tools needed to write and edit and format text and to send it to a printer	an application that provides the user with tools needed to write and edit and format text and to send it to a printer