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Slippery liquid-infused porous surface
A slippery liquid-infused porous surface (SLIPS) is a porous solid infused with liquid lubricant that repels water, oils, ice, and blood, introduced at Harvard in 2011.
Slipway
A slipway is a sloping structure, inclined toward the water, on which ships are built and launched; the patent slip of 1818 hauls vessels out for cheap repair.
Sloop
A sloop is a sailing vessel with one mast, a fore-and-aft rig, and two sails: a headsail ahead of the mast and a mainsail behind it.
Sloop-of-war
A sloop-of-war was an unrated sailing warship with fewer than 20 guns, used for patrol and escort duties; the French equivalent was called a corvette.
Slopaganda
Slopaganda is a term, coined by Michał Klincewicz, Mark Alfano, and Amir Fard in a 2025 paper, for AI-generated content used to manipulate beliefs for political ends.
Slope deflection method
The slope deflection method is a classical structural analysis method for finding member end moments in indeterminate beams and frames, introduced by George A. Maney in 1915.
Slope stability analysis
Slope stability analysis is the geotechnical engineering method for assessing whether a soil or rock slope will remain stable, by computing a factor of safety against sliding.
Sloped armour
Sloped armor is armor plate mounted at an angle to the expected line of fire, lengthening a projectile's path and causing ricochets, made famous by the Soviet T-34.
Slopsquatting
Slopsquatting is a software supply-chain attack where an adversary registers a package name hallucinated by a code-generating AI model, coined by Seth Larson in April 2025 by analogy with typosquatting.
Slot antenna
A slot antenna is a radiator formed by cutting an aperture in a conductive surface, used from 300 MHz to 24 GHz in radar and UHF TV broadcasting.
Slot filling
Slot filling is a natural language processing task that extracts specific attribute values, called slots, from unstructured text to fill a fixed template or knowledge base entry.
Slot trading
Slot trading is the buying, selling, leasing, or swapping of airport slots, the take-off and landing authorizations airlines hold, as a secondary market at congested airports.
Slot-die coating
Slot-die coating is a pre-metered coating process that delivers liquid through a fixed slot onto a moving substrate, producing uniform thin films with preset thickness.
Slotline
Slotline is a planar microwave transmission medium proposed by S. B. Cohn in 1968. It features a narrow gap in a dielectric substrate to support frequencies in the 60 to 200 ohm range.
Slotted line
A slotted line is a microwave measurement instrument whose movable probe, slid along a slotted transmission line, measures VSWR and impedance, tracing to Heinrich Hertz's 1888 experiments.
Slotting (warehouse management)
Slotting in warehouse management is the assignment of stock-keeping units to bin locations to minimize picking time and maximize accuracy; slotting optimization plans placement by demand, and re-slotting revises assignments as demand shifts.
Slovak Telekom
Slovak Telekom is Slovakia's largest telecommunications operator, providing fixed-line, mobile, internet, and TV services. Deutsche Telekom bought the remaining 49% stake in 2015 for €900 million.
Slovakia election deepfake audio
The Slovakia election deepfake audio was an AI-faked recording released two days before the 2023 parliamentary election, an early case of AI audio interfering with an election.
Slovalco
Slovalco is an aluminum smelter and casthouse in Žiar nad Hronom, Slovakia, majority-owned by Hydro. It curtailed primary production in 2022–2023 during the energy crisis and began restarting in 2026.
Slovenské Elektrárne
Slovenské Elektrárne is a Slovak electricity company, the country's largest producer, with nuclear and hydro plants owned 66% by the Czech group EPH since 2025.
Slovnaft
Slovnaft is a Slovak oil refining and petrochemicals company based in Bratislava, operating the country's only large refinery and largest filling-station chain, majority-owned by Hungary's MOL Group since 2000.
Slow feature analysis
Slow feature analysis is an unsupervised learning algorithm that extracts slowly varying features from fast-changing input signals, capturing stable underlying causes; it is used in machine learning and computational neuroscience.
Slow match
A slow match, or match cord, is chemically treated cord that smolders slowly without an open flame, used to ignite matchlock firearms and some cannons.
Slow pyrolysis
Slow pyrolysis is the thermal decomposition of biomass at a low heating rate and long residence time without oxygen, producing biochar as its main product.
Slow sand filter
A slow sand filter is a drinking-water treatment device in which water passes slowly through fine sand, whose biologically active surface layer removes pathogens; first used at Paisley, Scotland, in 1804.
Slow scan television
Slow scan television (SSTV) is an amateur radio method for sending still images as audio tones within a 3 kHz voice channel, conceived by Copthorne MacDonald in 1957.
Slow strain rate testing
Slow strain rate testing (SSRT) is a corrosion test that pulls a metal specimen to failure in a harsh environment to screen for stress corrosion cracking.
Slow-start (computer networks)
Slow-start is the startup phase of TCP congestion control, in which the sender's congestion window grows exponentially, doubling each round trip, until capacity or a threshold is reached.
Slowloris (cyberattack)
Slowloris is a denial-of-service attack tool released by researcher RSnake in 2009 that exhausts web servers by holding many incomplete HTTP connections open with little bandwidth.
Slowly changing dimension
A slowly changing dimension (SCD) is a data warehousing technique, introduced by Ralph Kimball in 1996, for managing changes to dimension attributes by overwriting, adding rows, or adding columns.