S
- Donatien Alphonse Francois de Sade, or, the Marquis de Sade, whose writings gave the name to sadism.
- Sheikh Safi-ad-din Ardabili — Safavid Dynasty, Safavids
- Leopold von Sacher-Masoch, one of the first to write of the pleasures of pain and humiliation, now called masochism
- Franz Sacher, Vienna — Sachertorte
- Ulrich Salchow — Salchow, Figure skating jump
- Salmanazar biblical king — 9 litre wine bottle (see Wine bottle#Sizes)
- Vasili Samarsky-Bykhovets, a Russian mine official — samarskite, the mineral after which the chemical element samarium has been named.
- John Montagu, 4th Earl of Sandwich — sandwiches and South Sandwich Islands
- Sappho (630 BC–612 BC), Greek poetess who wrote love poems addressed to women — sapphism or lesbianism
- Sarah Payne - Sarah's Law
- Muhammad bin Saud — Saudi Arabia
- Pierre Auguste Sarrus — Sarrusophone, a double-reed woodwind instrument made of brass or silver.
- Adolphe Sax — the saxophone, a musical instrument he invented
- Bernhard Schmidt - Schmidt camera telescope
- Louie Schmitt, animator — Louie, one of "Huey, Dewey and Louie", animated cartoon characters
- Walter H. Schottky, German physicist — Schottky diode
- Erwin Schrödinger — Schrödinger equation, Schrödinger's cat, Schrödinger's Kittens — a book
- Ed Scott — the second letter of the company name BEA Systems, is taken from Ed, a co-founder
- Robert Scott, Antarctic explorer — Amundsen-Scott South Pole Station
- Ebenezer Scrooge, fictional character in Charles Dickens' A Christmas Carol — Scrooge McDuck
- Glenn T. Seaborg — seaborgium, chemical element
- Richard Sears and Alvah Roebuck — Sears, Roebuck; stores bear only the Sears name
- Chief Seattle — City of Seattle
- Thomas Johann Seebeck — Seebeck effect
- Josef Sekanina — mineral Sekaninaite
- Edgar Selwyn and Archibald Selwyn, who used the last three letters of their name along with the first four of Samuel Goldfish to create Goldwyn Picture Corporation, which later merged into Metro-Goldwyn-Mayer (or MGM)
- Serendip — serendipity
- Otep Shamaya - Otep, a Los Angelean heavy metal band
- Adi Shamir — the second letter of the name RSA, an asymmetric algorithm for public key cryptography, is taken from Shamir
- Sherlock - short for Sherlock Holmes, anyone who solves a mystery or a difficult problem, based on the fictional character by Sir Arthur Conan Doyle
- Roger Shepard — Shepard tone
- Henry S. Shrapnel (1761–1842) — shrapnel
- Henry Miller Shreve (1785–1851) Steamboat captain for whom the city of Shreveport, Louisiana is named.
- Jean Sibelius (composer) — Sibelius notation program, and its developer Sibelius Software Ltd
- Ambrose Burnside (1824–1881) — Sideburns
- Werner von Siemens — siemens — unit of electrical conductance; Siemens AG — company
- Rolf Sievert — sievert, unit of radiation dose equivalent
- Etienne de Silhouette (1709–1767) — Silhouette
- Homer Simpson cartoon figure from The Simpsons — "doing a homer"; meaning to accidentally save the day from disaster
- Issac Merritt Singer, inventor, improvements in the design of the sewing machine — Singer Corporation
- Alexander Skene — Skene's gland
- BF Skinner - behaviorist who created the operant conditioning chamber -- which is often called the Skinner box
- Emil Škoda - founder, Škoda
- Horace Smith and Daniel B. Wesson - Smith & Wesson
- Edward Smith-Stanley, 12th Earl of Derby - Derby (horse race), particularly the Epsom Derby
- Oliver R. Smoot — smoot
- Hermann Snellen — Snellen chart
- Snot, a Saxon landowner ("Snot's home" + shire) — Nottinghamshire
- Socrates - Socratic Method
- Alexey Sokolsky — Sokolsky Opening
- Solomon — Solomon Islands
- John Philip Sousa — the Sousaphone musical instrument
- Thomas Spencer - Marks and Spencer
- William Archibald Spooner (1844–1930) — spoonerism
- Joseph Stalin — Stalinism and Neo-Stalinism (also see De-Stalinization), see List of places named after Joseph Stalin, Joseph Stalin Museum, Stalinist architecture, Stalin Society, Stalin Prize, Stalin Peace Prize, Iosif Stalin tank
- Johannes Stark — Stark spectroscopy, Stark effect
- Howard Staunton — Staunton Gambit
- Jozef Stefan and Ludwig Boltzmann — Stefan-Boltzmann constant
- Carl von Sternberg (disputed) — Reed-Sternberg cell
- George M. Sternberg (disputed) — Reed-Sternberg cell
- John K. Stewart and Arthur P. Warner — Stewart-Warner
- George Gabriel Stokes — stokes, unit of viscosity
- Marshall Harvey Stone — Stone–von Neumann theorem, Stone–Čech compactification, Stone's representation theorem for Boolean algebras, Stone space, Stone-Weierstrass theorem, Stone's representation theorem for distributive lattices, Stone duality, Stone's theorem on one-parameter unitary groups, Banach-Stone theorem
- Antonio Stradivari — Stradivari violin
- Levi Strauss — Levi Strauss & Co.
- Barbra Streisand - Lent name to the Streisand effect, censorship that has the unintended consequence of publicizing the information more widely.
- Count Stroganov (possibly Count Pavel Alexandrovitch Stroganov or Count Grigory Stroganov) — Stroganoff
- John McDouall Stuart - Stuart Highway, Central Mount Stuart
- Rashid Sunyaev and Yakov B. Zel'dovich — Sunyaev-Zel'dovich effect
- Michio Suzuki — founder, Suzuki
- Sage Kambu Swayambhuva — Cambodia
- Shirley Temple - Shirley Temple Soda
- Theodor Svedberg — svedberg, unit of sedimentation rate
Read more about this topic: List Of Eponyms (L-Z)