¹ Source: wiktionary.com
Medical Definition of White blood cells
1. White blood cells (WBCs) are cells which circulate in the blood and lymphatic system and harbor in the lymph glands and spleen. They are part of the immune system responsible for both directly (t cells and macrophages) and indirectly (B-cells producing antibodies) attacking foreign invaders of the body. (12 Dec 1998)