Haemolysins

Part of speech: noun

Definitions

1. Toxic proteins produced by certain bacteria that break open and destroy red blood cells by lysing their membranes
2. Substances secreted by some microbes that rupture the membranes of red blood cells, releasing their haemoglobin
3. Bacterial poisons capable of dissolving erythrocytes, causing the release of hemoglobin into the surrounding fluid

Etymology: "Haemolysins" is the plural of "haemolysin", a substance that breaks open red blood cells. The word is formed from two Greek-derived parts: "haemo-", from Greek "haima", meaning blood, and "-lysin", from Greek "lysis", meaning loosening or dissolving, combined with the suffix "-in", used in English to name a protein or chemical substance. Together they describe something that dissolves blood. Because the word is a modern scientific coinage built from classical roots, the ancient Greeks had no word like it, and nobody in antiquity would have recognised the idea of a substance that destroys red cells. The pattern is the same as in many other technical terms, where classical elements are assembled to name a discovery made in a much later period.