Which term describes a new and abnormal tissue formation or growth?

The term "neoplasm" refers specifically to a new and abnormal growth of tissue that can develop in the body. This term encompasses both benign (non-cancerous) and malignant (cancerous) tumors, indicating any uncontrolled proliferation of cells that forms a mass. Neoplasms arise from various cell types and can vary in their potential to harm the host and in their biological behavior.

Carcinoma pertains specifically to malignant tumors that arise from epithelial tissue, so it is a more restricted term within the broader classification of neoplasms. The term "benign" describes non-cancerous neoplasms that typically do not invade surrounding tissues or metastasize, while "adipoma" refers specifically to a fatty tumor, which is a subtype of benign neoplasms. However, "neoplasm" serves as the blanket term covering all types of abnormal tissue growths, making it the most accurate choice in the context of the question.