ADP vs EDP

ADP and EDP both are nouns.

Word	Noun	Adjective	Verb	Adverb
ADP	Yes	No	No	No
EDP	Yes	No	No	No

As nouns, EDP is a hyponym of ADP; that is, EDP is a word with a more specific, narrower meaning than ADP:

ADP: data processing by a computer
EDP: automatic data processing by electronic means without the use of tabulating cards or punched tapes

Other hyponyms of ADP include electronic data processing, IDP, integrated data processing.

ADP (noun)	EDP (noun)
data processing by a computer	automatic data processing by electronic means without the use of tabulating cards or punched tapes
an ester of adenosine that is converted to ATP for energy storage