Wiktionary
truth value
n. (context logic English) A value indicating to what extent a statement is true; in classical logic, these are the values "true" and "false".
Wikipedia
Truth value
In logic and mathematics, a truth value, sometimes called a logical value, is a value indicating the relation of a proposition to truth.
Usage examples of "truth value".
The truth value of a scientific statement is not affected by debating skill or the persuasive powers of a trained advocate.
That is three-point-seven percent, giving an error rate of ninety-six-point-three for the truth value of the entire statement.