white blood cell
Americannoun
noun
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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.
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Also called leukocyte
Other Word Forms
Noun Inflected Forms
Etymology
Origin of white blood cell
First recorded in 1885–90
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
They also found that while high white blood cell counts are usually a warning sign, in serious infection a low count can signal the immune system is becoming overwhelmed.
From BBC ● Jun. 16, 2026
Doctors at Columbia Presbyterian Hospital in New York first noticed Schlossberg’s irregular white blood cell count hours after she gave birth to her second child in May 2024, according to the essay.
From The Wall Street Journal ● Dec. 30, 2025
After the delivery, her doctor became alarmed by her high white blood cell count.
From Los Angeles Times ● Nov. 22, 2025
"If you take a blood sample before and after a cold swim, white blood cell levels do rise," she explains.
From BBC ● Nov. 21, 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
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
