1. [adv]  toward the south
2. [adj]  moving toward the south; "a southbound train"

SOUTHWARD is a 9 letter word that starts with S.

1. \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.
   
   

2. \South"ward\, a.
   Toward the south.
   
   

3. \South"ward\, n.
   The southern regions or countries; the south. --Sir W.
   Raleigh.