White blood cell is another name for a leukocyte.
Additional information:- 
Blood:- Blood is a red coloured liquid which flows in blood vessels and circulates in our body. 
Blood consists of four components:
★ Plasma : Plasma carries water and dissolved substances such as digested food and waste products from one part to another part in the body. 
★ Red Blood Cells ( RBC ) : Red blood cells carry oxygen from lungs to all the cells of the body. 
★ White Blood Cells ( WBC ) : White blood cells fight infection and protect us from diseases. 
★ Platelets : Platelets help in the clotting of blood in a cut or wound.