Accessory spleen, also known as splenunculus, is a small, secondary organ found in the human body. Synonyms for accessory spleen include supernumerary spleen, splenule, and ectopic spleen. These terms are used to describe the presence of an extra spleen-like structure, which is typically smaller in size and located outside the main spleen. While the main function of the spleen is to filter blood and aid in immune response, accessory spleens may contribute to blood cell production and storage as well. These synonyms are commonly used by medical professionals to describe this anatomical variation and its implications on overall health and well-being.