A reticulocyte is best defined as what type of cell?

A reticulocyte is best defined as an immature red blood cell. These cells are produced in the bone marrow and released into the bloodstream, where they will further mature into fully functional red blood cells. Reticulocytes still contain remnants of ribosomal RNA, which can be detected through special staining techniques, distinguishing them from mature erythrocytes.

In the context of erythropoiesis, reticulocytes play a crucial role as they indicate the activity of bone marrow in response to the body's need for red blood cells. An increased count of reticulocytes in the blood can signify recovering from anemia or increased production of red blood cells due to various stimuli, such as blood loss or hemolysis.