point of departure vs jumping-off place

point of departure and jumping-off place both are nouns.

Word	Noun	Adjective	Verb	Adverb
point of departure	Yes	No	No	No
jumping-off place	Yes	No	No	No

As nouns, point of departure and jumping-off place are synonyms defined as:

point of departure and jumping-off place: a place from which an enterprise or expedition is launched

point of departure (noun)	jumping-off place (noun)
a beginning from which an enterprise is launched	a place from which an enterprise or expedition is launched
a place from which an enterprise or expedition is launched