Meridional

a.
  1. Of or pertaining to the meridian.
  2. Having a southern aspect; southern; southerly.
    3. Meridional distance ,
    the distance or departure from the meridian; the easting or westing.
    Meridional parts ,
    parts of the meridian in Mercator's projection, corresponding to each minute of latitude from the equator up to 70 or 80 degrees; tabulated numbers representing these parts used in projecting charts, and in solving cases in Mercator's sailing.