Which term is synonymous with a red blood cell?

The term that is synonymous with a red blood cell (RBC) is actually "erythrocyte," which is not presented in the options. However, among the provided choices, "target cell" refers specifically to a type of red blood cell that has an abnormal appearance—characterized by a central area of hemoglobin surrounded by a ring of pallor. This can occur in various health conditions, such as liver disease or hemoglobinopathies, making it associated with red blood cells but not synonymous.

Granulocytes, thrombocytes, and macrophages are distinct types of blood cells. Granulocytes are a type of white blood cell involved in the immune response. Thrombocytes, also known as platelets, play a critical role in blood clotting. Macrophages are large immune cells derived from monocytes, responsible for phagocytosis of pathogens and debris.

Target cells are one form of red blood cells that reflect certain pathological states, indicating their link to the red blood cell family, thus providing a connection, albeit not a synonym, between the terms presented.