All articles starting with S

Standard score

A standard score, commonly called a z-score, expresses how far an observation lies from its distribution's mean, measured in standard deviations, with values typically between −3 and 3.

Standard siren

A standard siren is an astronomical source, typically a merging compact binary, whose gravitational-wave signal directly encodes its distance, allowing measurements of the Hubble constant.

Standard Solar

Standard Solar is an American commercial and community solar developer, financier, and asset owner in Rockville, Maryland, founded in 2004 and owned by Brookfield Renewable since 2022.

The standard solar model is a calibrated, one-dimensional mathematical description of the Sun's interior, evolved to its present age of 4.57 billion years and used as the reference for solar neutrino fluxes and helioseismology.

Standard solution

A standard solution is a solution of accurately known concentration, prepared by dissolving a substance of high purity or by standardizing against a primary standard, and used in titrations and instrumental calibration.

Standard step method

The standard step method is an iterative procedure that solves the one-dimensional energy equation step by step between cross sections to compute water surface profiles in open channels.

Standard streams

Standard streams, also called standard channels, are the three predefined input and output channels (stdin, stdout, and stderr) that every running process receives, corresponding to file descriptors 0, 1, and 2.

Standard temperature and pressure

Standard temperature and pressure (STP), or standard conditions, is a reference condition for comparing gas measurements, defined by IUPAC as 0 °C and 1 bar.

Standard Template Library

The Standard Template Library, or C++ STL, is a generic C++ library of containers, algorithms, and iterators designed by Alexander Stepanov and Meng Lee at Hewlett-Packard Labs.

Standard terminal arrival route

A standard terminal arrival route (STAR) is a preplanned IFR air traffic control arrival procedure guiding aircraft from the en route structure to an approach fix.

Standard time

Standard time is the official local clock time of a region when daylight saving time is not in use, first adopted by US and Canadian railroads in 1883.

Standard translation

The standard translation is a translation in modal logic that rewrites propositional modal formulas as first-order logic formulas, turning modal operators into quantifiers over possible worlds.

Sep 29, 2026

Standard triple therapy

Standard triple therapy is a Helicobacter pylori eradication regimen combining a proton pump inhibitor with amoxicillin and clarithromycin twice daily, now recommended only where clarithromycin resistance is low.

Standard uncertainty

Standard uncertainty is the estimated standard deviation, denoted u, used to express every component of measurement uncertainty so components can be combined under the GUM framework.

Standard wire gauge

Standard wire gauge, also called British Standard Wire Gauge or Imperial wire gauge, is the legal British standard for wire diameter by gauge number, fixed by Order in Council in 1883.

Standard work

Standard work, also called standardized work, is a lean manufacturing method documenting the best-known way to combine person, machine, and material in a job, enabling consistent repetition and kaizen.

Standard works

The Standard Works are the four canonized scriptures of the Church of Jesus Christ of Latter-day Saints: the Bible, Book of Mormon, Doctrine and Covenants, and Pearl of Great Price.

Standard-definition television

Standard-definition television (SDTV) is a class of digital television formats with lower picture resolution than high definition, typically 480 or 576 active lines in 4:3 or 16:9.

Standard-essential patent

A standard-essential patent (SEP) is a patent without which a product cannot implement a technology standard such as Wi-Fi or 4G, typically licensed on fair, reasonable, and nondiscriminatory terms.

Standard-gauge railway

A standard-gauge railway, also known as Stephenson gauge, has rails 1,435 mm apart, a spacing proposed by George Stephenson and now the world's most widely used railway gauge.

Standard-Model Extension

The Standard-Model Extension is an effective field theory combining the Standard Model with General Relativity plus all possible Lorentz-violating operators, introduced by Colladay and Kostelecký in 1998.

StandardAero

StandardAero is an independent provider of aerospace engine maintenance, repair, and overhaul services, headquartered in Scottsdale, Arizona, and tracing its origins to a 1911 Winnipeg machine shop.

Standardbred

Standardbred, American harness racing horse breed, trotters and pacers pulling a sulky; named for the 1879 2:30-mile registration standard, founded on Messenger and Hambletonian 10 (foaled 1849).

Standardization

Standardization is the consensus process by which experts, industry, and government develop voluntary standards specifying requirements for products, processes, and services, which become binding when adopted into contracts or regulation.

Standardization of Cart Axles (Che Tong Gui)

Standardization of Cart Axles (车同轨), recorded in the Shiji, was a Qin dynasty unification measure generally read as requiring uniform cart dimensions, though scholars dispute what it required.

Standardization of script, weights, measures, currency, and axle widths

Standardization of script, weights, measures, currency, and axle widths (書同文、車同軌) refers to measures ordered by Qin Shihuang in 221 BC to unify writing, laws, measures, coinage, and cart axle widths.

Standardization of the script

Standardization of the script (書同文) was the Qin dynasty policy of unifying Chinese writing, recorded in the Shiji, with small seal as the official standard.

Standardization of weights and measures

Standardization of weights and measures (统一度量衡) was the Qin dynasty's empire-wide unification of length, capacity, and weight standards, ordered by the First Emperor in 221 BC.

Sep 29, 2026

Standardized patient simulation

Standardized patient simulation is a medical education method in which trained people portray patients realistically and repeatably so learners can practice and be assessed on clinical skills.