English Dictionary

onto

/ˈɒn.tuː/

adj

(mathematics, of a function) Assuming each of the values in its codomain; having its range equal to its codomain.

The ball rolled onto the field.

意味（1）

(mathematics, of a function) Assuming each of the values in its codomain; having its range equal to its codomain.

Considered as a function on the real numbers, the exponential function is not onto.