Proposition: A statement in language that is or can be verified as true or false.

The meaning of declarative sentences or assertions, which must have a truth-value of truth or falsity.

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.