This document provides definitions and outlines the nomenclature and characteristics of benign and malignant tumors. It defines neoplasia as new abnormal growth and discusses how tumors are named based on the tissue of origin. Benign tumors are well-differentiated, slow growing, and remain localized, while malignant tumors are poorly differentiated, grow rapidly, can invade locally and metastasize to other sites. The document compares features of benign versus malignant tumors such as differentiation, growth rate, local invasion and metastasis.