IPA: //ˈsaʊθˌbaʊnd//
KK: /ˈsaʊθˌbaʊnd/
Moving or traveling in the direction of the south.
The southbound train will arrive at 3 PM.
Southbound → It is formed from "south" (from Old English *sūþ*, meaning the direction toward the south) and "bound" (from Old English *bund*, meaning to be tied or destined). The word "southbound" means destined or directed toward the south.
Think of the direction 'south' and remember that 'southbound' means heading or tied to that direction.