All articles starting with S
44,216 articles
Semigroup
A semigroup is an algebraic structure consisting of a non-empty set with an associative binary operation, sitting between a magma and a monoid in the hierarchy of algebraic structures.
Semigroup algebra
A semigroup algebra, also called a semigroup ring, is a ring of finite formal sums of semigroup elements multiplied by the semigroup operation, generalizing the polynomial ring.
Semihydrogenation
Semihydrogenation is the partial hydrogenation of an alkyne to an alkene, stopping before the alkane. The Lindlar catalyst gives cis alkenes, and industry uses it to remove acetylene from ethylene.
Semil Shah
Semil Shah is an American venture capitalist who founded the seed firm Haystack Ventures in 2013, known for early investments in DoorDash, Figma, HashiCorp, Carta, and Applied Intuition.
Semilab
Semilab is a Hungarian metrology equipment maker founded in 1989 by physicists from the Hungarian Academy of Sciences, headquartered in Budapest with subsidiaries across Asia and the United States.
Semilattice
A semilattice, also called an upper or lower semilattice, is a set with an associative, commutative, idempotent operation, equivalently a poset where every pair has a join or meet.
Semiluzhensky Ostrog
Semiluzhensky Cossack ostrog (Семилуженский казачий острог): a private reconstruction of a 17th-century Cossack fort in Semiluzhki village near Tomsk, built from 2009 by Vladimir Ilyin, now an interactive open-air museum on the historic Siberian tract.
Semimartingale
A semimartingale is a càdlàg adapted stochastic process decomposable into a local martingale plus a finite variation process, the largest class of integrators usable in Itô calculus.
Semimetal
A semimetal is a crystalline material in which conduction and valence bands overlap slightly, conducting like a metal with few carriers; examples include bismuth, antimony, arsenic, and graphite.
Seminary
A seminary, from the Latin seminarium meaning "seed bed," is an institution for theological education preparing religious leaders; the system dates to the Council of Trent, with Andover the first U.S. Protestant seminary in 1807.
Semino Rossi
Semino Rossi, born Omar Ernesto Semino in Rosario, Argentina in 1962, is an Argentine-Italian Schlager singer based in the Austrian Tyrol with millions of records sold.
Seminole
The Seminole are a Native American people formed in 1700s Florida from Creek and other migrants; three wars and removal produced three federally recognized tribes in Florida and Oklahoma.
Seminole County, Florida, United States
Seminole County, Florida: central Florida county founded April 25, 1913 from Orange County, seat Sanford, seven cities, 470,856 residents (2020), 491,884 (2025 estimate), 309 square miles, high-income Orlando suburb.
Seminole Electric Cooperative
Seminol Electric Cooperative is a not-for-profit generation and transmission electric cooperative headquartered in Tampa, Florida, serving nine member cooperatives that reach about 2 million people.
Seminole Generating Station
Seminole Generating Station is a coal-fired power station in Putnam County, Florida, operated by Seminole Electric Cooperative, with one 714 MW coal unit after Unit 1 retired in 2024.
Seminole Nation
The Seminole Nation of Oklahoma is a federally recognized Native American nation headquartered in Wewoka, descended from Seminoles forcibly removed from Florida in the nineteenth century.
Seminole Nation of Indian Territory
The Seminole Nation of Indian Territory was the self-governing Seminole polity in present-day Oklahoma, established by an 1856 treaty after the tribe's removal from Florida and dissolved before statehood.
Seminole NGL Pipeline
The Seminole NGL Pipeline is a 1,281-mile natural gas liquids pipeline in the United States, running from Hobbs on the Texas-New Mexico border to Mont Belvieu, Texas.
Seminole power station
Seminole power station, officially the Seminole Generating Station, is a 1,701 MW natural-gas-fired plant operated by Oklahoma Gas & Electric at Konawa, Oklahoma, with units from 1971 to 1975.
Seminole Tribe of Florida
Federally recognized Native American tribe in Florida, distinct from the Miccosukee Tribe; descendants of Seminoles who avoided 19th-century removal, never signed a peace treaty, ratified a 1957 constitution, and now run Hard Rock International and seven casinos.
Seminole Wars
The Seminole Wars were three conflicts between the Seminole people of Florida and the United States (First 1817-18, Second 1835-42, Third 1855-58), driven by Indian removal, costing about $30 million, and ending with removal to Oklahoma.
Seminoma
Seminoma, also called pure seminoma or classical seminoma, is a slow-growing germ cell cancer of the testicle in young men; it does not produce AFP, may raise beta-hCG, and is highly curable with orchiectomy, surveillance, carboplatin, radiotherapy, or BEP chemotherapy.
Semion Mogilevich (Семён Юдкович Могилевич)
Semion Mogilevich (Семён Юдкович Могилевич), born 1946 in Kyiv, alleged Eastern European organized-crime figure, YBM Magnex $150 million securities fraud, US-indicted, $5 million reward, never convicted, believed in Moscow.
Semionova Tien-Shanskogo (HP Ala-Archa)
Semionova Tien-Shanskogo (пик Семёнова-Тянь-Шаньского), also Ala-Archa High Point, is a 4,895 m ultra-prominent peak in Kyrgyzstan's Kyrgyz Ala-Too Range, its highest point, in Ala-Archa National Park, first climbed in 1950.
Semiotic analysis
Semiotic analysis is a method in linguistics and philosophy for interpreting texts, images, and gestures by examining how meaning is produced within sign systems such as language, pictures, and bodily movement.
Semiotics
Semiotics, also called semiology, is the study of signs and sign systems, founded independently in the late 1800s by Charles Sanders Peirce and Ferdinand de Saussure.
Semiotics and sociology of the actor
The semiotics of the actor is a research tradition treating the stage actor as a producer of organized signs, begun by the Prague Linguistic Circle and surveyed again in 2025.
Semipalatinsk Test Site (Семипалатинский испытательный полигон)
The Semipalatinsk Test Site (Семипалатинский испытательный полигон), known in Kazakhstan as the Polygon, was the Soviet Union's principal nuclear testing ground, hosting 456 nuclear tests from 1949 to 1989.
Semiparametric efficiency
Semiparametric efficiency is a theory in statistics that extends the Cramér–Rao bound to models with an infinite-dimensional nuisance parameter, giving the smallest achievable asymptotic variance.
Semiparametric model
A semiparametric model is a statistical model that combines a finite-dimensional parameter of interest with an infinite-dimensional nuisance component, sitting between parametric and nonparametric models.