the most primitive, undeveloped blood cell.
                                                            
                                                     
                        
                                                
                        
                        
                            Earliest stem cells; can mature into all cell types in the blood, but also maintain their own numbers
                                                            
                                                     
                        
                                                
                        
                        
                            Any stem cell that has the same functional capacity—that is, stable pluripotency—as an embryonic stem cell, though not necessarily the same origin.