a wire inside a hearing aid that can help people hear better on the telephone, and that can receive sound signals sent from an induction loop (= an electronic system in a public place, for example a theatre, that sends such signals)

The telecoil, which is a small magnetic coil in the hearing aid, helps improve sound during telephone calls. 电传线圈是助听器里一个小小的磁线圈，可帮助改善打电话时候的声音。

Telecoil or “T-coil” technology is a common feature on hearing aids that can enhance your hearing in difficult listening environments. 电传线圈或"T线圈"技术是助听器的一种常见功能，可以在困难的听觉环境中帮您提高听力。