IPA: /ˈhɛd.wɜrd/
KK: /hɛdˌwɜrd/
In the direction of the head or top; towards the head.
The river flows headward, moving towards the source.
Headward → It is formed from "head" (from Old English "heafod", meaning the upper part of the body or leader) and "-ward" (meaning in the direction of). The word "headward" means in the direction of the head or towards the top.
Think of moving 'in the direction of' ('-ward') the 'head' — that's why headward means towards the head.