To have faith or confidence.To exercise trust or confidence; rely through faith: generally with on.To be persuaded of the truth of anything; accept a doctrine, principle, system, etc., as true, or as an object of faith: with in: as, “I believe in the Holy Ghost, the holy Catholic Church, the communion of saints,” etc., Apostles' Crecd; to believe in Buddhism. See belief.To credit upon the ground of authority, testimony, argument, or any other ground than complete demonstration; accept as true; give credence to. See belief.To give credence to (a person making a statement, anything said, etc.).To expect or hope with confidence; trust.To be of opinion; think; understand: as, I believe he has left the city.