white blood cell

American  

noun

1. any of various nearly colorless cells of the immune system that circulate mainly in the blood and lymph and participate in reactions to invading microorganisms or foreign particles, comprising the B cells, T cells, macrophages, monocytes, and granulocytes.

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white blood cell British  

noun

1. a nontechnical name for leucocyte

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white blood cell Scientific  

/ wīt /

1. Any of various white or colorless cells in the blood of vertebrate animals, many of which participate in the inflammatory and immune responses to protect the body against infection and to repair injuries to tissues. White blood cells are formed mainly in the bone marrow, and unlike red blood cells, have a cell nucleus. The major types of white blood cells are granulocytes, lymphocytes, and monocytes. White blood cells are far less numerous in the blood than red blood cells, but their amount usually increases in response to infection and can be monitored as part of a clinical assessment.

2. Also called leukocyte

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Etymology

Origin of white blood cell

First recorded in 1885–90

Example Sentences

One assessed aging across multiple cell types and tissues, while the other focused specifically on monocytes, a type of white blood cell involved in immune responses.

From Science Daily • May 4, 2026

The path to chemotherapy began with a 1943 wartime disaster in Bari, Italy, where sailors exposed to mustard gas showed severely depleted white blood cell counts.

From The Wall Street Journal • Apr. 24, 2026

After the birth of her second child, her doctor noticed her white blood cell count was high.

From Los Angeles Times • Jan. 2, 2026

The human digestive system relies on two main kinds of macrophages, a type of specialized white blood cell, to maintain intestinal health.

From Science Daily • Nov. 3, 2025

However, the nodes in John’s neck were much harder, and his white blood cell count much higher, than would have been the case in someone with TB.

From "Mountains Beyond Mountains" by Tracy Kidder and Michael French