- onto (US spelling)
- Upon; on top of.
- My cat just jumped on to the keyboard.
- (informal) Aware of.
- The thought-police were on to my plans of world domination.
- Used to indicate, or signpost, logical progression to a new topic in a talk or discourse.
- Now. On to the system of active water uptake.
- Let's go on to item 3 in the list.