ADP vs automatic data processing

ADP and automatic data processing both are nouns.

Word	Noun	Adjective	Verb	Adverb
ADP	Yes	No	No	No
automatic data processing	Yes	No	No	No

As nouns, ADP and automatic data processing are synonyms defined as:

ADP (noun)	automatic data processing (noun)
data processing by a computer	data processing by a computer
an ester of adenosine that is converted to ATP for energy storage