standard time, civil time used within a given time zone. The earth is divided into 24 time zones, each of which is about 15° of longitude wide and corresponds to one hour of time. Within a zone all civil clocks are set to the same local solar time. Adjacent zones typically differ by a whole hour, although there are instances, such as in Newfoundland and South Australia, of half-hour zones. Standard time is based on universal time. Standard time was largely the creation of the Canadian railway engineer Sir Sandford Fleming (1827-1915). Its establishment in the United States was mainly due to the efforts of the educator Charles Dowd and William Allen, secretary of the American Railroad Association. Standard time officially came into existence after a 19-nation White House meeting in 1884, with the prime meridian established at Greenwich, England. In the United States, time zones are regulated by the Dept. of Transportation.

See also daylight saving time.

standard temperature and pressure: see STP.

standard schnauzer: see schnauzer.

standard of living, level of consumption that an individual, group, or nation has achieved. The evaluation of a standard of living is relative, depending upon the judgment of the observer as to what constitutes a high or a low scale. A relative index to the standard of living of a certain economic group can be gathered from a comparison of the cost of living and the wage scale or personal income. Factors such as discretionary income are important, but standard of living includes not only the material articles of consumption but also the number of dependents in a family, the environment, the educational opportunities, and the amount spent for health, recreation, and social services. Unemployment, low wages, crowded living conditions, and physical calamities, such as drought, flood, or war, may bring a drop in the standard of living, and, conversely, an increase in social benefits and higher wages may bring about a rise. While standard of living may vary greatly among various groups within a country, it also varies from nation to nation, and international comparisons are sometimes made by analyzing gross national products, per capita incomes, or any number of other indicators from life expectancy to clean water. Overall, industrialized nations tend to have a higher standard of living than developing countries. In the United States, as in most Western nations, the standard of living has shown a steady trend upward.

international gold standard: see international monetary system.

gold standard: see bimetallism; international monetary system; money.

Standard Model, in physics: see elementary particles.

American Standard Code for Information Interchange: see ASCII.

Official local time of a region or country. Local mean solar time depends on longitude; it advances by four minutes per degree eastward. The Earth can thus be divided into 24 standard time zones, each approximately 15° in longitude. The actual boundaries of each time zone are determined by local authorities and in many places deviate considerably from 15°. The times in different zones usually differ by an integral number of hours; minutes and seconds are the same. Seealso Greenwich Mean Time.

Learn more about standard time with a free trial on Britannica.com.

Level of material comfort that an individual or group aspires to or may achieve. This includes not only privately purchased goods and services but collectively consumed goods and services such as those provided by public utilities and governments. A standard of living determined for a group such as a country must be examined critically in terms of its constituent values. If the mean value increases over time, but at the same time the rich become richer and the poor poorer, the group may not be collectively better off. Various quantitative indicators can be used as measuring rods, including life expectancy, access to nutritious food and a safe water supply, and availability of medical care.

Learn more about standard of living with a free trial on Britannica.com.

In physics, the combination of two theories of particle physics into a single framework to describe all interactions of subatomic particles except those due to gravity (see gravitation). The two theories, the electroweak theory and the theory of quantum chromodynamics, describe the interactions between particles in terms of the exchange of intermediary particles. The model has proved highly accurate in predicting certain interactions, but it does not explain all aspects of subatomic particles. For example, it cannot say how many particles there should be or what their masses are. The search goes on for a more complete theory, and in particular a unified field theory describing the strong, weak, and electromagnetic forces.

Learn more about standard model with a free trial on Britannica.com.

Monetary standard under which the basic unit of currency is defined as a stated quantity of silver. It is usually characterized by the coinage and circulation of silver, unrestricted convertibility of other money into silver, and the free import and export of silver for the settlement of international obligations. No country now operates under a silver standard. In the 1870s most European countries adopted the gold standard, and by the early 1900s only China, Mexico, and a few small countries still used the silver standard. In 1873 the U.S. Treasury stopped coining silver, which led to the Free Silver Movement, but the defeat of William Jennings Bryan ended agitation for free silver in the U.S. Seealso bimetallism.

Learn more about silver standard with a free trial on Britannica.com.

Monetary system in which the standard unit of currency is a fixed quantity of gold or is freely convertible into gold at a fixed price. The gold standard was first adopted in Britain in 1821. Germany, France, and the U.S. instituted it in the 1870s, prompted by North American gold strikes that increased the supply of gold. The gold standard ended with the outbreak of World War I in 1914; it was reestablished in 1928, but because of the relative scarcity of gold, most nations adopted a gold-exchange standard, supplementing their gold reserves with currencies (U.S. dollars and British pounds) convertible into gold at a stable rate of exchange. Though the gold-exchange standard collapsed during the Great Depression, the U.S. set a minimum dollar price for gold, an action that allowed for the restoration of an international gold standard after World War II. In 1971 dwindling gold reserves and an unfavourable balance of payments led the U.S. to suspend the free convertibility of dollars into gold, and the gold standard was abandoned. Seealso bimetallism; exchange rate; silver standard.

Learn more about gold standard with a free trial on Britannica.com.

Monetary standard or system based on the use of two metals, traditionally gold and silver, rather than one (monometallism). In the 19th century, a bimetallic system defined a nation's monetary unit by law in terms of fixed quantities of gold and silver (thus automatically establishing a rate of exchange between the two metals). The system provided a free and unlimited market for the two metals, imposed no restrictions on the use and coinage of either metal, and made all other money in circulation redeemable in either gold or silver. Because each nation independently set its own rate of exchange between the two metals, the resulting rates of exchange often differed widely from country to country. When the ratio of the official prices proved different from the ratio of prices in the open market, Gresham's law operated in such a way that coins of only one metal remained in circulation. A monometallic system using the gold standard proved more responsive to changes in supply and demand and was widely adopted after 1867. Seealso exchange rate; silver standard.

Learn more about bimetallism with a free trial on Britannica.com.

in full American Standard Code for Information Interchange.

Data-transmission code used to represent both text (letters, numbers, punctuation marks) and noninput device commands (control characters) for electronic exchange and storage. Standard ASCII uses a string of 7 bits (binary digits) for each symbol and can thus represent 2⁷ = 128 characters. Extended ASCII uses an 8-bit encoding system and can thus represent 2⁸ = 256 characters. While ASCII is still found in legacy data, Unicode, with 8-, 16-, and 32-bit versions, has become standard for modern operating systems and browsers. In particular, the 32-bit version now supports all of the characters in every major language.

Learn more about ASCII with a free trial on Britannica.com.