Eosinophil

Part of speech: noun

Pronunciation: /i.əˈsɪnəˌfɪl/

Definitions

1. This category of white blood cell is essential for immune defense against helminths and is involved in hypersensitivity responses, easily identified by the granules that absorb eosin dye
2. A type of white blood cell, recognized for its role in combating parasitic infections and mediating allergic reactions, can be distinguished by its granules that stain with eosin dye
3. This immune cell plays a significant role in the body's defense against multicellular parasites and contributes to allergic inflammation, characterized by granules that take up eosin dye

Etymology: Eosinophil is a compound built from parts of Greek and a dye name. The dye, eosin, was named from Ancient Greek "ēōs", meaning "dawn", because of its rosy red colour. The suffix "-in" was added in the usual chemical way, so eosin is literally a "dawn-coloured" substance. The cell takes its name from the dye because its granules take up eosin readily when stained. "-o-" is a linking vowel, and "-phil" comes from Greek "philos", "loving", so the name means something like "eosin-loving". The word was formed in German, and the English term follows that pattern. The name describes a laboratory observation rather than the cell's function. Eosin was used as a stain in microscopy, and cells that showed a strong affinity for it were given a label based on that behaviour, not on what they did in the body.