CHOP is an acronym that stands for Cyclophosphamide, Hydroxydaunorubicin (also known as Doxorubicin), Oncovin (Vincristine), and Prednisone. It is a combination chemotherapy regimen commonly used to treat various types of non-Hodgkin lymphoma, including diffuse large B-cell lymphoma. This regimen aims to target and kill rapidly dividing cancer cells while minimizing damage to normal cells.