[[File:RandomBitmap.png|thumb|alt=|A [[Pseudorandom Number Generator|pseudorandomly generated]] [[bitmap]]. ]]
In common parlanceusage, '''randomness''' is the apparent or actual lack of [[pattern]] or [[predictability]] in events.<ref>The ''[[Oxford English Dictionary]]'' defines "random" as "Having no definite aim or purpose; not sent or guided in a particular direction; made, done, occurring, etc., without method or conscious choice; haphazard."</ref><ref name=":0">{{Cite web|url=https://www.dictionary.com/browse/randomness|title=Definition of randomness {{!}} Dictionary.com|website=www.dictionary.com|language=en|access-date=2019-11-21}}</ref> A random sequence of events, [[symbol]]s or steps often has no [[:wikt:order|order]] and does not follow an intelligible pattern or combination. Individual random events are, by definition, unpredictable, but if the [[probability distribution]] is known, the frequency of different outcomes over repeated events (or "trials") is predictable.<ref group="note">Strictly speaking, the frequency of an outcome will converge [[almost surely]] to a predictable value as the number of trials becomes arbitrarily large. Non-convergence or convergence to a different value is possible, but has [[probability]] zero.</ref> For example, when throwing two [[dice]], the outcome of any particular roll is unpredictable, but a sum of 7 will tend to occur twice as often as 4. In this view, randomness is not haphazardness; it is a measure of uncertainty of an outcome. Randomness applies to concepts of chance, [[probability]], and [[information entropy]].
The fields of mathematics, probability, and statistics use formal definitions of randomness. In statistics, a [[random variable]] is an assignment of a numerical value to each possible outcome of an [[event space]]. This association facilitates the identification and the calculation of probabilities of the events. Random variables can appear in [[random sequence]]s. A [[random process]] is a sequence of random variables whose outcomes do not follow a [[determinism|deterministic]] pattern, but follow an evolution described by [[probability distribution]]s. These and other constructs are extremely useful in [[probability theory]] and the various [[applications of randomness]].
