Call of Duty: Black Ops Cold War – PlayStation 4

4 (four) is a number, numeral and digit. It is the natural number following 3 and preceding 5.

4 is the smallest square number > 1, the smallest semiprime and composite number, and the 3rd highly composite number.

The number 4 is considered unlucky in many East Asian cultures.

Black is a color that results from the absence or complete absorption of visible light. It is an achromatic color, without hue, like white and grey. It is often used symbolically or figuratively to represent darkness. Black and white have often been used to describe opposites such as good and evil, the Dark Ages versus the Age of Enlightenment, and night versus day. Since the Middle Ages, black has been the symbolic color of solemnity and authority, and for this reason it is still commonly worn by judges and magistrates.

Black was one of the first colors used by artists in Neolithic cave paintings. It was used in ancient Egypt and Greece as the color of the underworld. In the Roman Empire, it became the color of mourning, and over the centuries it was frequently associated with death, evil, witches, and magic. In the 14th century, it was worn by royalty, clergy, judges, and government officials in much of Europe. It became the color worn by English romantic poets, businessmen and statesmen in the 19th century, and a high fashion color in the 20th century. According to surveys in Europe and North America, it is the color most commonly associated with mourning, the end, secrets, magic, force, violence, fear, evil, and elegance.

Black is the most common ink color used for printing books, newspapers and documents, as it provides the highest contrast with white paper and thus is the easiest color to read. Similarly, black text on a white screen is the most common format used on computer screens. As of September 2019, the darkest material is made by MIT engineers from vertically aligned carbon nanotubes.

Cold is the presence of low temperature, especially in the atmosphere. In common usage, cold is often a subjective perception. A lower bound to temperature is absolute zero, defined as 0.00 K on the Kelvin scale, an absolute thermodynamic temperature scale. This corresponds to −273.15 °C on the Celsius scale, −459.67 °F on the Fahrenheit scale, and 0.00 °R on the Rankine scale.

Since temperature relates to the thermal energy held by an object or a sample of matter, which is the kinetic energy of the random motion of the particle constituents of matter, an object will have less thermal energy when it is colder and more when it is hotter. If it were possible to cool a system to absolute zero, all motion of the particles in a sample of matter would cease and they would be at complete rest in the classical sense. The object could be described as having zero thermal energy. Microscopically in the description of quantum mechanics, however, matter still has zero-point energy even at absolute zero, because of the uncertainty principle.

A duty (from "due" meaning "that which is owing"; Old French: deu, did, past participle of devoir; Latin: debere, debitum, whence "debt") is a commitment or expectation to perform some action in general or if certain circumstances arise. A duty may arise from a system of ethics or morality, especially in an honor culture. Many duties are created by law, sometimes including a codified punishment or liability for non-performance. Performing one's duty may require some sacrifice of self-interest.

A sense-of-duty is also a virtue or personality trait that characterizes someone who is diligent about fulfilling individual duties or who confidently knows their calling. A sense-of-duty can also come from a need to fulfill familial pressures and desires. This is typically seen in a militaristic/patriotic way.

Cicero, an early Roman philosopher who discusses duty in his work “On Duties", suggests that duties can come from four different sources:

1. as a result of being a human
2. as a result of one's particular place in life (one's family, one's country, one's job)
3. as a result of one's character
4. as a result of one's own moral expectations for oneself

The specific duties imposed by law or culture vary considerably, depending on jurisdiction, religion, and social normalities.

In ancient Roman religion, Ops or Opis (Latin: "Plenty") was a fertility deity and earth goddess of Sabine origin. Her equivalent in Greek mythology was Rhea.

PlayStation is a video gaming brand that consists of five home video game consoles, two handhelds, a media center, and a smartphone, as well as an online service and multiple magazines. The brand is produced by Sony Interactive Entertainment, a division of Sony.

The first PlayStation console was released in Japan in December 1994, and worldwide the following year. The original console in the series was the first console of any type to ship over 100 million units, doing so in under a decade. Its successor, the PlayStation 2, was released in 2000; it is the best-selling home console to date, having reached over 155 million units sold by the end of 2012. Sony's next console, the PlayStation 3, was released in 2006, selling over 87.4 million units by March 2017. Sony's next console, the PlayStation 4, was released in 2013, selling a million units within a day, becoming the fastest selling console in history. The latest console in the series, the PlayStation 5, was released in 2020 and sold 10 million units in its first 249 days, unseating its predecessor as the fastest-selling PlayStation console to-date. The main series of controllers utilized by the PlayStation series is the DualShock, a line of vibration-feedback gamepads that sold 28 million units by June 2008.

The first handheld console in the series, the PlayStation Portable (PSP), sold a total of 80 million units worldwide by November 2013. Its successor, the PlayStation Vita (PSVita), which launched in Japan in December 2011 and in most other major territories in February 2012, sold over four million units by January 2013. PlayStation TV is a microconsole and a non-portable variant of the PlayStation Vita handheld game console. Other hardware released as part of the PlayStation series includes the PSX, a digital video recorder which was integrated with the PlayStation and PlayStation 2, though it was short-lived due to its high price and was never released outside Japan, as well as a Bravia television set which has an integrated PlayStation 2.

The PlayStation Network is an online service with about 110 million registered users (as of June 2013) and over 103 million active users monthly. (as of December 2019) It comprises an online virtual market, the PlayStation Store, which allows the purchase and download of games and various forms of multimedia, a subscription-based online service known as PlayStation Plus and a social gaming networking service called PlayStation Home, which had over 41 million users worldwide at the time of its closure in March 2015. PlayStation Mobile (formerly PlayStation Suite) is a software framework that provides PlayStation content on mobile devices. Version 1.xx supports both PlayStation Vita, PlayStation TV and certain devices that run the Android operating system, whereas version 2.00 released in 2014 only targeted PlayStation Vita and PlayStation TV. Content set to be released under the framework consist of only original PlayStation games currently.

Seventh generation PlayStation products also use the XrossMediaBar, which is an Technology & Engineering Emmy Award–winning graphical user interface. A touch screen-based user interface called LiveArea was launched for the PlayStation Vita, which integrates social networking elements into the interface. Additionally, the PlayStation 2 and PlayStation 3 consoles also featured support for Linux-based operating systems; Linux for PlayStation 2 and OtherOS respectively, though this has since been discontinued. The series has also been known for its numerous marketing campaigns, the latest of which being the "Greatness Awaits" and eventually, "Play Has No Limits" commercials in the United States.

The series also has a strong line-up of first-party games due to PlayStation Studios, a group of many studios owned by Sony Interactive Entertainment that exclusively developed them for PlayStation consoles. In addition, the series features various budget re-releases of games by Sony with different names for each region; these include the Greatest Hits, Platinum, Essentials, and The Best selection of games. It is also known for the four iconic PlayStation face buttons (, , , ).

War is an armed conflict between the armed forces of states, or between governmental forces and armed groups that are organized under a certain command structure and have the capacity to sustain military operations, or between such organized groups. It is generally characterized by extreme violence, destruction, and mortality, using regular or irregular military forces. Warfare refers to the common activities and characteristics of types of war, or of wars in general. Total war is warfare that is not restricted to purely legitimate military targets, and can result in massive civilian or other non-combatant suffering and casualties.

While some war studies scholars consider war a universal and ancestral aspect of human nature, others argue it is a result of specific socio-cultural, economic, or ecological circumstances.