The Collaborative International Dictionary of English v.0.48:
Succursal \Suc*cur"sal\, a. [Cf. F. succursale. See Succor, n. & v. t.] Serving to aid or help; serving as a chapel of ease; tributary. [R.] [1913 Webster] Not a city was without its cathedral, surrounded by its succursal churches, its monasteries, and convents. --Milman. [1913 Webster]