All articles A–Z
519,064 articles
Subduction
Subduction is the process at a convergent plate boundary in which one tectonic plate, usually the denser oceanic plate, sinks beneath another into the mantle.
Subdural hematoma
Subdural hematoma: bleeding between the dura mater and brain surface, usually from torn bridging veins after head injury. Acute forms are surgical emergencies; chronic forms affect older adults, and middle meningeal artery embolization now reduces recurrence after drainage.
Subdural hygroma
Subdural hygroma (SDHy, SDG): a subdural collection of pure CSF from traumatic arachnoid tearing or effusion in intracranial hypotension, dehydration, or atrophy; coined by Dandy 1934; may convert to chronic subdural hematoma.
Subdwarf
A subdwarf is a star fainter than a main-sequence star of the same spectral type but brighter than a white dwarf of the same temperature, in luminosity class VI.
Subdwarf B star
A subdwarf B star (sdB) is a subluminous, low-mass star burning helium in its core under an extremely thin hydrogen envelope, defined by Sargent and Searle in 1968.
Subedaar (film)
Subedaar (सुबेदार) is a 2026 Hindi action-drama on Prime Video, directed by Suresh Triveni, starring Anil Kapoor as retired soldier Arjun Maurya fighting a sand mafia, with Radhikka Madan, Mona Singh, and Aditya Rawal; released March 5, 2026.
Subedar (صوبیدار)
Subedar (صوبیدار) is a senior South Asian army rank, once the highest open to Indian soldiers under British rule as a Viceroy's Commissioned Officer, now a Junior Commissioned Officer rank in the Indian, Pakistani, and Bangladeshi armies.
Subependymal giant cell astrocytoma
Subependymal giant cell astrocytoma (SEGA), a benign slow-growing grade 1 brain tumor of the ventricle walls, occurring almost exclusively in tuberous sclerosis complex; treated by surgery or everolimus.
Subependymoma
Subependymoma: rare WHO grade 1 ependymal tumor of the brain or spinal cord, mainly in adults around age 50, arising in the fourth and lateral ventricles, with excellent prognosis after surgical resection.
Subepithelial connective tissue graft
A subepithelial connective tissue graft is a periodontal surgery technique, reported by Burton and Laureen Langer in 1985, using palatal connective tissue to cover exposed tooth roots and thicken gum tissue around teeth and implants.
Subepithelial mucinous corneal dystrophy
Subepithelial mucinous corneal dystrophy (SMCD) is a rare autosomal dominant corneal disorder, first described in 1993, causing painful recurrent erosions in childhood and progressive corneal clouding in adulthood.
Suberites
Suberites Nardo, 1833: genus of velvety smooth demosponges (family Suberitidae) with tylostyle spicules; type species S. domuncula, a hermit-crab-associated Mediterranean sponge; not monophyletic, with cryptic Arctic lineages.
Suberites domuncula
Suberites domuncula, basionym Alcyonium domuncula, is an orange globular demosponge of the Mediterranean and nearby Atlantic that overgrows hermit crab shells and serves as a model for innate immunity.
Suberosis
Suberosis (corkworker's lung, ICD-10 J67.3, ICD-11 CA70.3) is a hypersensitivity pneumonitis of cork workers caused by moldy cork dust, mainly Penicillium glabrum or P. frequentans, first identified in 1955.
Subfactor
A subfactor is an inclusion of factors within von Neumann algebras, a theory initiated by Vaughan Jones in the early 1980s, whose Jones index takes quantized values.
Subfloor
A subfloor is the structural panel or board layer fastened across floor joists to form a load-bearing deck that supports finish flooring and helps the floor resist wind and seismic forces.
Subfocus DJ set & ID
Subfocus DJ set & ID covers the club and festival performances of Sub Focus, the British drum & bass producer Nicolaas Douwma, active since the early 2000s.
Subgame perfect equilibrium
Subgame perfect equilibrium is a refinement of Nash equilibrium for sequential games, introduced by Reinhard Selten in 1965, requiring equilibrium in every subgame and ruling out non-credible threats.
Subgenera and sections of Cortinarius
The subgenera and sections of Cortinarius sort one of the largest mushroom-forming fungal genera, with over 3,000 named species, into groups based on anatomy, pigments, and DNA.
Subgiant branch
The subgiant branch (SGB) is the Hertzsprung–Russell diagram region occupied by stars that have just left the main sequence, powered by hydrogen shell burning around an inert helium core.
Subgiant star
A subgiant is a luminosity class IV star that has exhausted its core hydrogen and is evolving from the main sequence toward the red-giant stage.
Subgingival Curettage
Subgingival curettage, also called gingival curettage or periodontal epithelial debridement, is removal of the epithelial lining of periodontal pockets with a curette; abandoned after trials showed no benefit over scaling and root planing.
Subglacial channel
A subglacial channel is a conduit carrying meltwater at a glacier bed, melted upward into the ice (an R-channel) or eroded downward into bedrock (a Nye channel).
Subglacial drainage
Subglacial drainage is the movement of meltwater at the base of a glacier or ice sheet through films, cavities, and channels, governing basal sliding, erosion, and outburst floods.
Subglacial lake on Mars
The subglacial lake on Mars is a putative body of liquid water proposed in 2018 beneath the south polar ice cap, based on radar reflections that remain contested.
Subglacial water on Mars
Subglacial water on Mars is hypothesized liquid water beneath the planet's ice, notably a putative lake 1.5 km below the south polar cap reported in 2018.
Subgrade
The subgrade in railway engineering is the compacted upper surface of the embankment fill or cutting that receives the ballast and must carry traffic loads without significant deformation.
Subgradient
A subgradient is a vector generalizing the gradient of a differentiable function to convex functions that may fail to be differentiable, defined by a supporting hyperplane to the graph.
Subgradient method
The subgradient method is a first-order optimization algorithm that minimizes nondifferentiable convex functions by repeatedly stepping against a subgradient, and it underlies stochastic gradient methods in machine learning.
Subgraph isomorphism
Subgraph isomorphism is the NP-complete computational problem of deciding whether a smaller pattern graph can be mapped into a larger host graph, used in cheminformatics, graph databases, and computer vision.