A diagnostic tool is a device or software used to identify and analyze problems within a system, often in fields like medicine, engineering, or information technology. These tools help professionals gather data, assess conditions, and determine the root causes of issues, enabling effective solutions. In healthcare, for example, a medical diagnostic tool like an MRI machine provides images of the body's internal structures, helping doctors diagnose conditions. In IT, software diagnostic tools can detect issues in computer systems, allowing technicians to troubleshoot and repair problems efficiently.