A Risk

1. (countable) A possible adverse event or outcome

Synonyms: danger, peril, hazard

2. The probability of a negative outcome to a decision or event.
3. The magnitude of possible loss consequent to a decision or event.
4. (formal use in business, engineering, etc.) The potential (conventionally negative) effect of an event, determined by combining the likelihood of the event occurring with the effect should it occur.
5. (countable, insurance) An entity insured by an insurer or the specific uncertain events that the insurer underwrites.

(formal business and engineering): variance, standard deviation, downside beta