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Alpha-synuclein
Alpha-synuclein (α-synuclein, SNCA gene product) is a 140-residue presynaptic protein; misfolded β-sheet aggregates form Lewy bodies in Parkinson's disease, dementia with Lewy bodies, and MSA, and seed amplification assays detect it diagnostically.
Alpha-thalassemia (α-thalassemia)
Alpha-thalassemia (α-thalassemia), also called alpha thalassemia, is an inherited anemia from HBA1/HBA2 alpha-globin gene deletions, ranging from silent carrier and trait to HbH disease and fatal Hb Bart hydrops fetalis; mitapivat approved 2025.
Alpha-thalassemia-intellectual disability syndrome linked to chromosome 16
ATR-16 syndrome (OMIM 141750), alpha-thalassemia-intellectual disability syndrome linked to chromosome 16, is a rare contiguous gene deletion of 16p13.3 removing HBA1/HBA2, causing alpha-thalassemia with variable intellectual disability, unlike X-linked ATR-X.
Alpha-thalassemia-myelodysplastic syndrome
Alpha-thalassemia-myelodysplastic syndrome (ATMDS, acquired hemoglobin H disease) is a rare acquired alpha-thalassemia caused by somatic ATRX mutations in myelodysplastic syndrome, affecting mainly older men, with about 80 cases reported.
Alpha-tocopherol
Alpha-tocopherol (α-tocopherol) is the principal vitamin E form, the only one meeting human requirements, selectively retained by hepatic alpha-tocopherol transfer protein; trial evidence on supplementation and mortality is mixed.
Alpha–beta pruning
Alpha–beta pruning, also called alpha–beta search, is a search algorithm that cuts the number of nodes minimax evaluates on a game tree without changing the root value.
Alphabaculovirus bomori
Alphabaculovirus bomori (Bombyx mori nucleopolyhedrovirus, BmNPV) is an ICTV baculovirus species infecting the silkworm; exemplar strain T3 has a 128,413 bp circular dsDNA genome (L33180) and BmNPV serves as a silkworm expression vector.
AlphaBay
AlphaBay was a darknet marketplace on Tor, online December 2014 to July 2017, selling drugs, weapons, malware, and stolen data for Bitcoin, Monero, and Ethereum. Founded by Alexandre Cazes (Alpha02), it was seized in Operation Bayonet as the largest darknet market to that date, with over $1 billion in transactions.
Alphabet
Alphabet: a writing system whose letters each represent a single phoneme, unlike abjads, abugidas, and syllabaries. Descends from proto-Sinaitic script via the 22-sign Phoenician alphabet to Greek, Latin, and Hebrew; possibly older Umm el-Marra finds remain debated.
Alphabet agencies
Alphabet agencies: the acronym-named U.S. federal agencies of FDR's New Deal (AAA, CCC, NRA, TVA, WPA, FDIC, SEC, and others), created mainly in 1933-1934 to deliver relief, recovery, and reform during the Great Depression.
Alphabet blocks
Alphabet blocks: lettered toy cubes for early literacy and building play, conceived by John Locke in 1693, shaped by Froebel's gifts, first mass-produced in America by S. L. Hill (1858 patent), inducted into the National Toy Hall of Fame in 2003.
Alphabet City, Manhattan
Alphabet City, Manhattan: East Village sub-neighborhood between Avenues A-D, Houston Street and 14th Street, named for its lettered avenues; also called Loisaida; known for Nuyorican culture, Tompkins Square Park, and gentrification since the 1990s.
Alphabet Inc.
Alphabet Inc. is an American technology holding company created in August 2015 to own Google and other businesses, reporting $402.8 billion in revenue and $132.2 billion in net income for 2025.
Alphabet murders
Alphabet murders, also called Double Initial murders: unsolved 1971–1973 killings of Carmen Colón, Wanda Walkowicz, and Michelle Maenza near Rochester, New York, whose alliterative names matched the towns where their bodies were found; no one was ever charged.
Alphabet of Sirach
The Alphabet of Sirach, usually called the Alphabet of Ben Sira, is a medieval Hebrew and Aramaic pseudepigraphic work attributed to Ben Sira, best known for its earliest Lilith story.
Alphabetical order
Alphabetical order, also called alphabetization, arranges words, names, or entries by the sequence of letters in an alphabet, so lists can be consulted letter by letter.
AlphaChip
AlphaChip is a deep reinforcement learning method developed by Google for chip floorplanning, placing large circuit blocks on a chip layout, published in Nature in 2021.
AlphaCode
AlphaCode is a Google DeepMind code-generation system for competitive programming, announced in February 2022, with a successor, AlphaCode 2, powered by Gemini Pro in 2023.
Alphacoronavirus porci
Alphacoronavirus porci, an ICTV coronavirus species in genus Alphacoronavirus (Coronaviridae), host pig; members attach via sialic acid and use aminopeptidase N (APN) as main receptor; distinct from Alphacoronavirus suis.
Alphacoronavirus suis
Alphacoronavirus suis (formerly Alphacoronavirus 1) is an ICTV coronavirus species in subgenus Tegacovirus grouping TGEV, PRCV, canine and feline coronaviruses infecting pigs, dogs, and cats; renamed from Alphacoronavirus 1 in 2023.
AlphaDev
AlphaDev is a reinforcement learning system released by Google DeepMind in June 2023 that found faster assembly-level sorting and hashing routines, several merged into LLVM libc++ and Abseil.
Alphadjo Cisse
Alphadjo Cissè is an Italian professional footballer, born in 2006 in Treviso, who plays as a midfielder for AC Milan, joining from Hellas Verona in 2026.
AlphaEvolve
AlphaEvolve is an evolutionary coding agent from Google DeepMind, announced in May 2025, that uses Gemini models and automated evaluators to evolve programs, improving matrix multiplication and datacenter scheduling.
AlphaFold
AlphaFold is a family of AI systems from Google DeepMind that predict protein structures from amino-acid sequences, recognized with the 2024 Nobel Prize in Chemistry.
AlphaFold 3
AlphaFold 3 is an AI model from Google DeepMind and Isomorphic Labs that predicts the 3D structure of protein, DNA, RNA, and drug complexes, announced in May 2024.
AlphaGeometry
AlphaGeometry is a neuro-symbolic theorem prover for Euclidean geometry from Google DeepMind and NYU, published in Nature in 2024, solving 25 of 30 olympiad-level problems.
AlphaGo
Developed by Google DeepMind, AlphaGo is a computer program that plays Go using deep neural networks and Monte Carlo search, achieving a historic win in 2015.
AlphaGo versus Ke Jie (柯洁)
AlphaGo versus Ke Jie (柯洁) was a three-game Go match in Wuzhen, China, in May 2017, in which AlphaGo Master beat world number one Ke Jie 3–0 and was then retired.
AlphaGo versus Lee Sedol
AlphaGo versus Lee Sedol was a five-game Go match in Seoul in March 2016, won 4–1 by Google DeepMind's program against South Korean master Lee Sedol (이세돌).
AlphaGo Zero
AlphaGo Zero: DeepMind's 2017 Go program that learned solely by self-play from random play, no human data. Beat AlphaGo Lee 100-0 after 3 days and AlphaGo Master 89-11 after 40 days, Elo 5,185.