A hazard is something that could cause harm or danger. A patch of ice on the sidewalk is a hazard because someone might slip and fall. A frayed electrical cord is a hazard because it could cause a fire or shock. In a laboratory, scientists wear safety goggles to protect their eyes from chemical hazards.

The word often appears in warnings and safety discussions. Fire hazard signs tell you something could start a fire. A health hazard might make you sick. When weather forecasters warn of hazardous driving conditions, they're saying the roads are dangerous because of snow, ice, or heavy rain.

In golf, a hazard means something different: it's an obstacle on the course, like a sand trap or a water hazard, that makes the game more challenging. Golfers try to avoid hitting their ball into these hazards.

You can also use hazard as a verb meaning to risk or venture something uncertain. A scientist might hazard a guess about an experiment's outcome, meaning she's offering her best estimate even though she's not completely sure. When you hazard a guess on a difficult question, you're taking a chance by answering even when you don't know for certain you're right.