depend
Pronunciation: /dɪˈpɛnd/
verb
- 1 (depend on/upon) be controlled or determined by: differences in earnings depended on a wide variety of factors


Origin:
late Middle English (in depend (sense 3); also in the sense 'wait or be in suspense'): from Old French dependre, from Latin dependere, from de- 'down' + pendere 'hang'

In informal use, it is quite common for the on to be dropped in sentences such as it all depends how you look at it (rather than it all depends on how you look at it), but in well-formed written English the on should be retained.