Short answers, pulled from the story.
The Oxford English Dictionary traces the earliest English use of the word "risk" - spelled "risque" from its French original - to 1621, with the modern spelling appearing in 1655. It entered the language initially as a synonym for "hazard," meaning a potential source of harm.
Frank Knight, in his 1921 work "Risk, Uncertainty, and Profit," argued that risk is measurable - it can be attached to a number and calculated - while uncertainty is immeasurable and cannot be quantified. Knightian uncertainty is therefore categorically different from risk, not simply a more severe form of it.
ISO 31000 defines risk assessment as the overall process of risk identification, risk analysis, and risk evaluation, taken in sequence. Risk identification finds and records risks; risk analysis determines their nature and level; risk evaluation compares estimated risk levels against criteria to guide decisions on treatment.
Mandelbrot defined mild risk as risk that follows normal or near-normal probability distributions, subject to regression to the mean and the law of large numbers, making it relatively predictable. Wild risk follows fat-tailed distributions such as Pareto or power-law distributions, where the mean or variance may be effectively infinite, making accurate prediction difficult or impossible.
Paul Slovic's psychometric paradigm holds that risk is subjectively defined by individuals and can be measured through surveys. Slovic argues that intuitive emotional reactions are the dominant way humans evaluate risk, and that purely statistical approaches to disasters fail to motivate adequate protective responses.
ALARP stands for "as low as reasonably practicable" and is a principle developed within the UK Health and Safety Executive's tolerability of risk framework. It applies to tolerable risks - those that fall between broadly acceptable and unacceptable - and requires organizations to weigh the costs and benefits of further risk reduction before deciding how much reduction is warranted.