From WordNet (r) 3.0 (2006) [wn]:
range of a function
n 1: (mathematics) the set of values of the dependent variable
for which a function is defined; "the image of f(x) = x^2
is the set of all non-negative real numbers if the domain
of the function is the set of all real numbers" [syn:
image, range, range of a function]