Risk  is the combination of the probability of occurrence of harm and the severity of the harm.

Harm: Injury or damage to the health of people, or damage to property or the environment.

Hazard: Potential source of harm.

Severity: Measure of the possible consequences of a hazard.

Hazardous situation: Circumstances in which people, property or environment is/are exposed to one or more hazards.

Risk Analysis: Systematic use of available information to identify hazards and estimate the risk.

Risk Assessment: Overall process containing risk analysis and a risk evaluation.