Sentinel lymph node biopsy, also known as SLNB, is a surgical procedure that involves the removal and examination of one or more lymph nodes that are the first to receive drainage from a tumor. This procedure is commonly used for the staging of breast cancer and melanoma. Synonyms for SLNB include sentinel node biopsy, sentinel node mapping, sentinel lymph node dissection, and sentinel node localization. All of these terms refer to the same procedure, and they may be used interchangeably depending on the context. Regardless of the terminology used, SLNB is an important tool for diagnosing and treating cancer, and it has revolutionized the way that tumors are staged and treated.