Oxyhemoglobin refers to the form of hemoglobin present in red blood cells when they are carrying oxygen. However, there are many other words that can be used synonymously with oxyhemoglobin. For instance, oxygenated hemoglobin or arterial hemoglobin can be used interchangeably with oxyhemoglobin. Similarly, oxygenated red blood cells or oxygenated blood can also be used to depict the presence of oxyhemoglobin in the blood. Some other synonyms for oxyhemoglobin are oxihemoglobin and oxyhaemoglobin, both of which can be used in the scientific literature. Regardless of the term used, however, all of these words refer to the critical role played by hemoglobin in the transportation of oxygen in the human body.