You searched for: “hemoglobin
hemoglobin, haemoglobin (s) (noun); hemoglobins; haemoglobins (pl)
The red coloring matter of the red corpuscles in the blood: Hemoglobin in the blood combines with oxygen and carries it around the body, for example from the lungs to the tissues, and carbon dioxide from the tissues to the lungs.
(Greek: "blood " plus Latin: "sphere, ball"; oxygen-carrying protein of the red corpuscles)