The Collaborative International Dictionary of English v.0.48:

Northing \North"ing\, n.
   1. (Surv. & Navigation) Distance northward from any point of
      departure or of reckoning, measured on a meridian; --
      opposed to southing.
      [1913 Webster]

   2. (Astron.) The distance of any heavenly body from the
      equator northward; north declination.
      [1913 Webster]