jumping-off place /ˌʤʌmpɪŋˈɔf-/
  出發點,山窮水盡的地步,遠僻處
  jumping-off place
       n : a place from which an enterprise or expedition is launched;
           "one day when I was at a suitable jumping-off place I
           decided to see if I could find him"; "my point of
           departure was San Francisco" [syn: point of departure]