The hazard rate refers to the rate of death for an item of a given age. It is part of a larger equation called the hazard function, which analyzes the likelihood that an item will survive to a certain point in time based on its survival to an earlier time. In other words, it is the likelihood that if something survives to one moment, it will also survive to the next. The hazard rate only applies to items that cannot be repaired and is sometimes referred to as the failure rate. It is fundamental to the design of safe systems in applications and is often relied on in commerce, engineering, finance, insurance, and regulatory industries.