dropping zone vs drop zone

dropping zone and drop zone both are nouns.

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

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

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

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