White corpuscles, commonly known as white blood cells, are an integral part of the human immune system. They help safeguard the body against infections and diseases by fighting against harmful bacteria, viruses, and other pathogens. Synonyms for white corpuscles include leukocytes, white cells, and white blood cells. The term leukocyte refers to any group of white blood cells that have a nucleus and no color granules. White cells, a less specific term, describes all cell types that lack the characteristic red color of erythrocytes. White blood cells are essential for maintaining a healthy immune system and defending against invaders that affect overall health and well-being.