drop zone vs dropping zone

drop zone and dropping zone both are nouns.

Word	Noun	Adjective	Verb	Adverb
drop zone	Yes	No	No	No
dropping zone	Yes	No	No	No

As nouns, drop zone and dropping zone are synonyms defined as:

drop zone and dropping zone: an agreed area where military supplies are dropped to ground troops

drop zone (noun)	dropping zone (noun)
an agreed area where military supplies are dropped to ground troops	an agreed area where military supplies are dropped to ground troops