surjection

/sərˈdʒɛkʃən/
noun
  1. In mathematics, a function that maps every element of the output set to at least one element of the input set; a function that is onto.
    • The teacher explained that a surjection covers every value in the target set.
    • A surjection is also called an onto function because it hits every possible output.
    • In our algebra class, we proved that the function f(x) = x^3 is a surjection from the real numbers to the real numbers.