Biohazard

Part of speech: noun

Pronunciation: /ˈbaɪəʊˌhæzəd/

Definitions

1. A biological or chemical substance that poses a threat to human health or the environment
2. A risk-inducing biological or chemical agent that endangers health and poses potential harm to ecosystems
3. Any living organism or its byproducts that can cause adverse effects on people or the environment due to their harmful nature

Etymology: Biohazard is a modern compound, and its story is more about what it was built to warn against than about ancient roots. Its first half comes from the Greek "bios," meaning life, which gave English the combining form "bio-". The second half, "hazard," arrived in English from Old French and originally referred to a game of dice before coming to mean danger in general. The pairing of those two parts produced a term for threats to living things. "Bio-" links the word to the living world, while "hazard" supplies the sense of risk. Together they describe a substance that threatens human health or the environment, most often one that is biological or chemical in origin. The word's use on warning signs, the familiar symbol of three overlapping circles, is what fixed it in everyday speech. Anyone who has seen that label on a lab door or a medical waste bin has encountered the term in its practical form.