Definitions function as rules for language rather than factual claims, which is why many philosophers argue they cannot be true or false.
Why Definitions Are Not True or False
Stipulative rules: When you create a definition, you assign a specific meaning to a word. You are making a choice, not stating a fact.
Lack of a truth value: In logic, a statement must assert a fact about the world to be true or false. A definition only sets a standard for how a word will be used.
Commands in disguise: A definition is similar to an agreement or a rule. You cannot test a rule to see if it is factually correct.