A set of input and output values where each input value has one or more output values is called a(n)?

A set of input and output values where each input value has one or more corresponding output values is called a "relation." In mathematical terms, it describes how each element from a set of inputs (domain) relates to elements in a set of outputs (codomain). Unlike a function, where each input has exactly one output, a relation can have multiple outputs for a single input.