Material biconditional

Material biconditional: A truth-functional sentence formed by connecting two sentences by ‘if and only if”; such sentences are true if and only if the two sentences connected have the same truth value. 

Source: ‘What is Good? What is Bad? The Value of All Values across Time, Place and Theories’ by John McMurtry, Philosophy and World Problems, Volume I-III, UNESCO in partnership with Encyclopedia of Life Support Systems: Oxford, 2004-11.