S is the nineteenth letter of the English alphabet.
S may also refer to:
South on a map, one of the 4 cardinal directions
s, the SI symbol for second
Shilling (British coin)
S postcode area, a postcode area including Sheffield, England
A party label for the Swedish Social Democratic Party
Strike (baseball)
S band, a band of radio which ranges from 2 to 4 GHz
Language and linguistics
Long s (ſ), a form of the lower-case letter s formerly used where "s" occurred in the middle or at the beginning of a word
-s, a suffix added to some English surnames, originally meaning "son of"
s, the IPA symbol for a voiceless alveolar sibilant sound
S, the subject of an intransitive verb
Mathematics and logic
Integral symbol (∫), used in mathematics to denote integrals and antiderivatives
S combinator in combinatory logic
Sphere
s(n), the aliquot sum of an integer n
Physics and chemistry
S, the chemical symbol for the element Sulfur on the periodic table
S, the symbol for entropy
S, a non-SI unit used to designate molecule size named after the Svedberg sedimentation coefficient
S, a label that denotes one of two chiral center configurations in the R/S system
s, one of the Mandelstam variables, the square of the invariant mass
Siemens (unit), the SI derived unit of electric conductance
S-block of the periodic table, which includes alkali metals, alkaline earth metals, and hydrogen and helium
Spin (physics)
Biology and medicine
Serine, a standard amino acid abbreviation
ATC code S Sensory organs, a section of the Anatomical Therapeutic Chemical Classification System
S phase or synthesis phase, a period in the cell cycle during interphase
Samsung Galaxy S, the first flagship smartphone of the Samsung Galaxy S series
S (programming language), an environment for statistical computing and graphics
<s>, the opening tag for the HTML element denoting information that is "no longer accurate or no longer relevant", usually rendered as strike-through text
S. (Dorst novel), written by Doug Dorst based on story by J.J. Abrams
S. (Updike novel), part of the Scarlet Letter trilogy by John Updike
S (novel series), a 2005-2006 light novel series
S, the pen name of Percy Bysshe Shelley
"S.", the nickname for Solomon Shereshevsky (1886-1958), a Russian journalist, mnemonist, and synesthete notable for his unusual memory abilities
S, the stage name of singer-songwriter and guitarist Jenn Ghetto
S (group), a short-lived South Korean music group active in 2003 and 2014
S (EP), a 2001 EP by Japanese musical duo NaNa
Numbering of Franz Liszt's works according to Humphrey Searle's catalogue
