biohazard

American  

[bahy-oh-haz-erd] / ˈbaɪ oʊˌhæz ərd /

noun

1. a pathogen, especially one used in or produced by biological research.

2. the health risk posed by the possible release of such a pathogen into the environment.

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biohazard British  

/ ˌbaɪəʊˈhæzəd /

noun

1. material of biological origin that is hazardous to humans

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biohazard Scientific  

/ bī′ō-hăz′ərd /

1. A biological agent, such as an infectious microorganism, that constitutes a threat to humans or to the environment, especially one produced in biological research or experimentation.

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Other Word Forms

• biohazardous adjective

Etymology

Origin of biohazard

bio- + hazard

Explanation

A biohazard is a biological substance that's dangerous to people or the environment. Many biohazards are made of bacteria or other microorganisms. Some biohazards are an unintentional side effect of biologists working with or studying toxins or viruses. One common type of biohazard is medical waste — things like used syringes or other tools contaminated with human blood, bacteria, or other microorganisms. The word biohazard was first used around 1973, from the Greek bio-, "life," and hazard, from the Old French hasard, "game of chance."

Example Sentences

Medinsky posted a photo on Telegram apparently showing the exchange, with individuals dressed in biohazard suits standing next to a line of white refrigerated trucks used to transport bodies.

From BBC • Jan. 29, 2026

But my green thumb ached as workers sawed down the tree, took away everything — trunk, twigs, leaves, fruit, roots — in biohazard bags and tagged the remaining trees with a bill of clean health.

From Los Angeles Times • Dec. 18, 2024

In August there were 23 mostly minor assault reports, consistent with other months, but guards led to more biohazard and misconduct events reported, said Wright.

From Seattle Times • Oct. 6, 2023

The fluid is also considered a potential biohazard.

From Scientific American • Aug. 22, 2023

It is highly infective, lethally hot, a liquid that would scare the daylights out of a military biohazard specialist.

From "The Hot Zone" by Richard Preston