A detector is a device used to detect the presence of an object or phenomenon. The crossword solutions for the term 'detector' include 'SENSOR' (6 letters), 'RADAR' (5 letters), 'LIE' (3 letters), 'sonar' (5 letters), and 'METAL' (5 letters). A SENSOR is a device that detects and responds to some type of input from the physical environment. RADAR is an object-detection system that uses radio waves to determine the range, angle, or velocity of objects. LIE is an untruthful statement. Sonar is a technique that uses sound propagation to detect objects underwater. METAL detectors are devices used to detect the presence of METAL objects.