knee.-to perceive or apprehend clearly and certainly; to understand; to have full information of; as, to know one's duty.-to be convinced of the truth of; to be fully assured of; as, to know things from information.-to be acquainted with; to be no stranger to; to be more or less familiar with the person, character, etc., of; to possess experience of; as, to know an author; to know the rules of an organization.-to recognize; to distinguish; to discern the character of; as, to know a person's face or figure.-to have sexual commerce with.-to have knowledge; to have a clear and certain perception; to possess wisdom, instruction, or information; -- often with of.-to be assured; to feel confident.