This word is acceptable for play in the US & UK dictionaries that are being used in the following games:

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n. The target space into which a function maps elements of its domain. It always contains the range of the function, but can be larger than the range if the function is not surjective.

"For example, if a unary function is considered as a set of ordered pairs, then the domain and codomain are given by the first and second projections, respectively."

domain   

range