All articles starting with S
44,216 articles
Subsea wellhead
A subsea wellhead is a set of pressure-containing housings, hangers, and seals installed on the seabed, suspending casing and supporting the blowout preventer during drilling.
Subsecretaría de Telecomunicaciones (Chile)
The Subsecretaría de Telecomunicaciones (SUBTEL) is the Chilean state agency that regulates telecommunications, including spectrum, concessions, and tariffs, created in 1977 under the Ministry of Transport and Telecommunications.
Subsequence
A subsequence of a sequence is a new sequence formed by deleting some terms and keeping the rest in their original order, so the indices must strictly increase.
Subsequent event
A subsequent event is an event occurring after the balance sheet date but before financial statements are issued, defined under IFRS's IAS 10 and US GAAP's ASC 855.
Subsequent myocardial infarction
Subsequent myocardial infarction (ICD-11 BA42; ICD-10 I22) is a heart attack occurring within 28 days of a previous one, clinically called re-infarction; diagnosed by recurrent ST elevation, new Q waves, or a >20% troponin rise.
Subset
A subset, also called a set inclusion, is a set all of whose members also belong to another set B, written A ⊆ B; a proper subset leaves at least one member out.
Subset sum problem
The subset sum problem asks whether some subset of a set of integers sums exactly to a target. It was proved NP-complete in Richard Karp's 1972 paper.
Subshift of finite type
A subshift of finite type, also called a Markov shift, is a set of infinite sequences avoiding a finite list of forbidden words, central to symbolic dynamics.
Subsidence
Subsidence, also called land or ground subsidence, is the sinking of the Earth's surface caused by groundwater pumping, mining, or soil drainage; over 80 percent of known US subsidence stems from groundwater use.
Subsidence analysis
Subsidence analysis is a geology method that reconstructs a basin's downward movement through time, using backstripping to remove sediment loading and isolate tectonic subsidence, whose curve shape diagnoses basin type.
Subsidiarity (Catholicism)
Subsidiarity in Catholicism: the principle of Catholic social teaching that higher authorities must not supplant individuals, families, local communities, and intermediary bodies, but aid and coordinate them for the common good; formulated in Quadragesimo anno (1931).
Subsidiary
A subsidiary, also called a subsidiary company or daughter company, is a company controlled by a parent or holding company, yet a separate legal entity.
Subsidiary alliance
Subsidiary alliance: East India Company treaty system, chiefly under Wellesley (Governor-General 1798–1805), by which Indian states ceded defence and foreign policy, paid for Company troops, and hosted Residents; Hyderabad signed first in 1798.
Subsidiary alliance system in Maratha states
The subsidiary alliance system in Maratha states (सहाय्यक संधी प्रणाली) was a set of treaties, begun with the Treaty of Bassein in 1802, that placed Maratha rulers under British control.
Subsidiary Alliance with Hyderabad
The Subsidiary Alliance with Hyderabad (معاہدہ امدادی) comprised two treaties, signed in 1798 and 1800, by which Nizam Asaf Jah II accepted a permanent East India Company force.
Subsidy
A subsidy is a payment or concession a government grants to firms, households, or other units, including tax breaks and price supports, to promote a public objective.
Subsistence agriculture
Subsistence agriculture, also called subsistence farming, is farming whose output goes primarily to feeding the farmer's own household rather than to being sold; the 50% consumption line is a common boundary.
Subsistence economy
A subsistence economy is one where production is aimed at the producer's own household or community rather than at sale, and it can still include markets and money.
Subsonic ammunition
Subsonic ammunition, also called subsonic rounds, is firearm ammunition loaded to a muzzle velocity below the speed of sound, eliminating the supersonic crack and used chiefly with sound suppressors.
Subspace clustering
Subspace clustering is an unsupervised machine learning method that groups data points assumed to lie near a union of low-dimensional subspaces, used in motion segmentation and face clustering.
Subspace Pursuit
Subspace Pursuit is an iterative greedy algorithm for reconstructing sparse signals from compressed measurements, proposed by Wei Dai and Olgica Milenkovic and published in IEEE Transactions on Information Theory in 2009.
Subspace theorem
The Subspace theorem is a 1972 result of Wolfgang M. Schmidt in Diophantine approximation, generalizing Roth's theorem: solutions of a product inequality in linear forms lie in finitely many subspaces.
Subspace topology
The subspace topology, also called the induced or relative topology, is the topology on a subset A of a space X whose open sets are the intersections U ∩ A.
Subspecies
Subspecies: taxonomic rank below species, named with a trinomen (e.g., Puma concolor coryi), for geographic or morphologically distinct populations not reproductively isolated; contested rank with proposed 75% and diagnosability criteria, used in conservation listings.
Subspecies of Canis lupus
Subspecies of Canis lupus: named geographic populations of the gray wolf, historically 32 worldwide (24 in North America), with genetics validating some, such as the Mexican wolf C. l. baileyi, and leaving North American designations unsettled.
Substack
Substack is a San Francisco subscription publishing platform founded in 2017 by Chris Best, Hamish McKenzie, and Jairaj Sethi. It takes 10% of subscription revenue, passed 5 million paid subscriptions in March 2025, and reached a $1.1 billion valuation in July 2025.
Substance 1987
Substance 1987 is New Order's first compilation album, released by Factory Records (FACT 200) in August 1987; it collects the band's 12-inch singles and B-sides, peaked at UK number 3, and sold over one million copies.
Substance abuse
Substance abuse, now diagnosed as substance use disorder under DSM-5, is compulsive use of alcohol or drugs despite harm. Covers neurobiology, 40-60% genetic risk, US prevalence, overdose trends, NPS monitoring, and treatments.
Substance abuse detection
Substance abuse detection, also called drug abuse screening, is the set of clinical methods for identifying drug or alcohol misuse through questionnaires, laboratory testing, and electronic health record analysis.
Substance dependence
Substance dependence, also called physical dependence, is a state in which the body needs a drug to function, marked by tolerance and withdrawal; distinct from addiction (substance use disorder), treatable with tapering and FDA-approved medications.