Wiktionary
truth function
alt. (context mathematics logic English) A Boolean function whose value is interpreted as truth or falsity n. (context mathematics logic English) A Boolean function whose value is interpreted as truth or falsity
Wikipedia
Truth function
In mathematical logic, a truth function is a function from a set of truth values to truth values. Classically the domain and range of a truth function are { truth, falsehood}, but they may have any number of truth values, including an infinity of these.