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.

---

white blood cell British  

noun

1. a nontechnical name for leucocyte

---

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

---

Etymology

Origin of white blood cell

First recorded in 1885–90

Example Sentences

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

When TL1A activates these cells, they draw large numbers of neutrophils, a type of white blood cell, from the bone marrow and alter their behavior in ways that promote tumor formation.

From Science Daily • Jan. 25, 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

Patients are also at risk of lymphoma, a cancer which affects a type of white blood cell.

From BBC • Jun. 26, 2025

And easy, you say, giggling, then dozing back off Bad Your white blood cell count is elevated, the doctor says.

From "Booked" by Kwame Alexander