Main Entry:

¹on·to

Pronunciation:

\ˈȯn-(ˌ)tü, ˈän-\

Function:

preposition

Date:

1581

1 : to a position on 2 : in or into a state of awareness about <put me onto your methods> 3 —used as a function word to indicate a set each element of which is the image of at least one element of another set <a function mapping the set S onto the set T>