A transporter inhibitor field, also known as a transport inhibitor was a forcefield used to prevent the operation of a transporter in a specified area.
Transporter inhibitor fields were heavily used in correctional settings to prevent the unauthorized transport of inmates away from the institution. For example, transporter inhibitor fields were in use at the New Zealand Penal Settlement on Earth and the Starfleet stockade on Jaros II. (DSC novel: Drastic Measures; ST - The Fall novel: The Poisoned Chalice)
A damaged Lieutenant Commander Data deployed a transporter inhibitor on the Ba'ku homeworld to prevent himself from being beamed away by a shuttle sent deployed by the USS Enterprise. After Data was recovered and repaired, Captain Picard and the senior staff of the Enterprise deployed transport inhibitors throughout the Ba'ku colony to prevent the Son'a from beaming them aboard their vessel. (TNG movie: Insurrection)