TDR, or Time Domain Reflectometry, is a term commonly used in the field of electrical engineering. It refers to the technique of measuring the time it takes for a signal to reflect back from a transmission line or cable, which in turn allows engineers to determine the length and other characteristics of the cable. There are several synonyms for TDR, including reflectometer, cable tester, and time domain reflectometer. These terms all describe the same technology and are often used interchangeably by professionals in the field. Regardless of which term is used, TDR remains an important tool for ensuring the functionality and safety of electrical systems.