multiprocessing vs parallel processing

multiprocessing and parallel processing both are nouns.

Word	Noun	Adjective	Verb	Adverb
multiprocessing	Yes	No	No	No
parallel processing	Yes	No	No	No

As nouns, multiprocessing and parallel processing are synonyms defined as:

multiprocessing and parallel processing: simultaneous processing by two or more processing units

multiprocessing (noun)	parallel processing (noun)
simultaneous processing by two or more processing units	simultaneous processing by two or more processing units