1.
To be ~ on something or someone means to need them in order to succeed or be able to survive.
The local economy is overwhelmingly ~ on oil and gas extraction...
= reliant
ADJ: oft ADJ on/upon n
2.
If one thing is ~ on another, the first thing will be affected or determined by the second.
The treatment of infertility is largely ~ on the ability of couples to pay.
= contingent
? in~
ADJ: v-link ADJ on/upon n
3.
see also dependant