An electromagnetic interference phenomenon where a signal transmitted on one circuit or channel creates an unwanted effect on another circuit or channel. In telecommunications and networking, crosstalk can lead to degradation of signal quality, resulting in communication errors or loss of data. It is more prevalent in older or improperly shielded cables and is a significant consideration in the design of high-speed data communication systems. Measures such as using twisted pair cables or proper cable management practices are employed to minimize crosstalk.