n. A unit of risk equivalent to a one-in-a-million probability of death.
A micromort (from micro- and mortality) is a unit of risk defined as one-in-a-million chance of death within the next year. Micromorts can be used to measure riskiness of various day-to-day activities. A microprobability is a one-in-a million chance of some event; thus a micromort is the microprobability of death. The micromort concept was introduced by Ronald A. Howard who pioneered the modern practice of decision analysis.
Micromorts for future activities can only be rough assessments as specific circumstances will always have an impact. However past historical rates of events can be used to provide a ball-park, average figure.