Duhaime's Law Dictionary Wire-tapping Definition: An electronic surveillance device which secretly listens in and records conversations held over a phone line. Related Terms: Eavesdroppers, Pen Register, Electronic Monitoring May also be known or referrred to as electronic surveillance. It is usually only allowed with the permission of a judge and if it can be shown to be necessary for the solving of a serious crime. Without proper authority for this serious intrusion into someone's privacy, wire-tapping may be in itself a crime. Always looking up definitions? Save time with our search provider (modern browsers only) If you find an error or omission in Duhaime's Law Dictionary, or if you have suggestion for a legal term, we'd love to hear from you!