The term 'Depth Finder' refers to a device used to measure the depth of water. It is composed of three components: SONIC (5 letters), SONAR (5 letters), and ZAXIS (5 letters). SONIC is an acoustic wave that is sent out from the device and reflects off the bottom of the water, allowing the device to measure the depth. Sonar is a type of technology that uses sound waves to detect objects underwater. ZAXIS is a type of sensor that measures the angle of the sound waves, allowing the device to accurately measure the depth of the water. Together, these three components make up a Depth Finder, which is used to measure the depth of water.