biohazard

noun

bio·​haz·​ard ˈbī-ō-ˌha-zərd 

: a biological agent or condition that is a hazard to humans or the environment

also : a hazard posed by such an agent or condition

biohazardous

ˌbī-ō-ˈha-zər-dəs 

adjective

Examples of biohazard in a Sentence

The gasoline spill created a serious biohazard.

Recent Examples on the Web

The team at PuroClean of North Metro Atlanta — often called in to clean up biohazards — is busy. —Kaley Fedko, CBS News, 5 Jan. 2026

Vacuum If there’s a possibility of coming across rotten food or mold in the fridge, biohazard expert and supervisor Gabby Martin of Bio Recovery urges you to use personal protective equipment (PPE) while cleaning. —Taylor Tobin, Southern Living, 1 Jan. 2026

Neighbors complained of odors emanating from the business after some animals in freezers were allowed to defrost, and in September, the city of San Marcos got a court order to enter the premises and hired a contractor to clean up the biohazard. —Karen Kucher, San Diego Union-Tribune, 4 Dec. 2025

Initially, the Fort Worth Stockyards’ twice daily cattle drive was paused out of caution after the Texas Animal Health Commission and The Texas Department of Agriculture called on horsemen to monitor their herds and take biohazard precautions. —Fousia Abdullahi, Fort Worth Star-Telegram, 28 Nov. 2025

Word History

First Known Use

1965, in the meaning defined above

Rhymes for biohazard

• haphazard
• hazard

Medical Definition

biohazard

noun

bio·​haz·​ard ˈbī-ō-ˌhaz-ərd, -ˈhaz- 

: a biological agent or condition (as an infectious organism or insecure laboratory procedures) that constitutes a hazard to humans or the environment

also : a hazard posed by such an agent or condition

biohazardous

-ˈhaz-ərd-əs 

adjective