Risk

Risk is the potential impact (positive or negative) to an asset or some characteristic of value that may arise from some present process or from some future event. In everyday usage, "risk" is often used synonymously with "probability" and restricted to negative risk or threat. more...

In professional risk assessments, risk combines the probability of an event occurring with the impact that event would be. Financial risk is often defined as the unexpected variability or volatility of returns, and thus includes both potential worse than expected as well as better than expected returns. References to negative risk below should be read as applying to positive impacts or opportunity (e.g. for loss read "loss or gain") unless the context precludes

Defined aspects of risk

The engineering definition of risk:

Risk is often mapped to the probability of some event which is seen as undesirable. Usually the probability of that event and some assessment of its expected harm must be combined into a believable scenario (an outcome) which combines the set of risk, regret and reward probabilities into an expected value for that outcome. (See also Expected utility)

-Could be used in the sentence: "It was definitely a risk walking through that neighborhood at night wearing a Ku Klux Klan costume", the amount of risk can also be put, for example a 45% Risk.

Thus in statistical decision theory, the risk function of an estimator δ(x) for a parameter θ, calculated from some observables x; is defined as the expectation value of the loss function L,

Read more at Wikipedia.org