@Fatihah,
Not my definition I assure you, but a significant one in epistemology and ontology. As I said, you are not equipped to examine your
conditioned thought processes. Discussion of the concepts of "proof" and "truth" is a bit like ice-skating, but you are unable to put the boots on.
On the basis of the layman's (dictionary) idea of "truth" how would
you (as a representative Muslim) cope with modern science like Quantum Theory, which one exponent has described by the phrase "Everything that can happen, does happen".? (Note that your computer hardware depends on such a theory).