Leucocytes

Part of speech: noun

Definitions

1. A type of white blood cell in the immune system that helps defend the body against infections and foreign substances
2. Cells in the bloodstream that are crucial for immune responses, fighting infections and maintaining health
3. Various kinds of white blood cells that play essential roles in the body's defense against pathogens and disease

Etymology: "Leucocytes" is the plural of "leucocyte," and the word is a plain modern compound. Its first half, "leuco-," comes from Ancient Greek "leukos," meaning "white," a root that also gives English words like "leukemia." The second half, "-cyte," is a scientific suffix built from Ancient Greek "kytos," meaning "hollow vessel" or "cell," which entered modern scientific vocabulary through Latin "cyta." The pieces were joined in English as a technical coinage, so the word is a product of nineteenth-century biology rather than of the ancient world. The Greeks had the ingredients but never put them together to name these cells, which were only identified as a distinct class once microscopes made blood visible in fine detail.

Synonyms: white blood cells, immune cells