Source : Webster's Revised Unabridged Dictionary (1913)

Southward \South"ward\ (?; colloq. ?), Southwards \South"wards\
   (?; colloq. ?), adv.
   Toward the south, or toward a point nearer the south than the
   east or west point; as, to go southward.

Source : WordNet®

southwards
     adv : toward the south [syn: {southward}]