What does leucocyte mean?
A leucocyte is a white blood cell: one of the immune-system cells found in blood, lymph, and many tissues. Leucocytes protect the body by identifying and dealing with infectious organisms, inflamed tissue, and abnormal cells. Major categories include lymphocytes, monocytes, and granulocytes, with each group performing specialized immune functions. The term is chiefly associated with medicine, biological research, and laboratory reports, where leucocyte counts and blood-cell differentials help clinicians assess infection, inflammation, and some immune disorders. The spelling leucocyte is especially associated with British usage, while leukocyte is more common in American English; both forms are accepted in technical writing. Although the word may initially sound unfamiliar, it follows a straightforward naming pattern: leucocyte literally means “white cell.” Knowing it allows a reader to understand a broad range of clinical and scientific information while distinguishing white blood cells from red blood cells and platelets.
nounA leucocyte is a white blood cell, one of the cells that form part of the body's immune system and help defend against infection and disease.
- Any of the various nucleated cells of the immune system that circulate in the blood, including lymphocytes, monocytes, and granulocytes.
"The blood test revealed an elevated leucocyte count, suggesting that the body was fighting an infection."
"The doctor ordered a complete blood count after the patient's leucocyte levels rose sharply."
"Researchers used fluorescence microscopy to identify individual leucocytes within the tissue sample."
The standard plural is leucocytes, with no change to the ending.
"The microscope revealed numerous leucocytes in the patient's blood sample."
Unlike red blood cells, leucocytes lack haemoglobin, which is why they are called “white” blood cells.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does leucocyte come from?
Leucocyte was formed in 19th-century scientific usage from Greek leukos, meaning “white,” and kytos, meaning “cell.” The name distinguishes these cells from the haemoglobin-containing red blood cells. The same Greek leuk- element appears in related terms such as leukemia, leukoderma, and leukorrhea, all associated etymologically with whiteness.
Related word forms
How leucocyte is actually used
Leucocyte is a formal biomedical term used chiefly in medicine, immunology, and laboratory science rather than in everyday discussion.
Easily confused with leucocyte
Leukocyte is the more common American spelling of the British form leucocyte; both names refer to the same type of white blood cell.
A lymphocyte is a specific type of white blood cell, whereas a leucocyte is the broader term encompassing lymphocytes and several other kinds.