A bugging device is a type of surveillance equipment used to secretly listen in on conversations. It is also known as a wiretap, eavesdropping device, or listening device. The term 'bugging device' comes from the phrase 'bugging out, ' which means to eavesdrop on someone. The crossword solution for the term 'bugging device' is TAP, which stands for Telephone Access Point. This is a device that is connected to a telephone line and allows someone to listen in on conversations without being detected.