ST, St, or St. most often refers to:
-st, a suffix for an ordinal numeral, such as 1 or 21 Saint, abbreviated "St" in (British and Commonwealth usage) and "St." elsewhere Street, e.g. in addresses
ST, St, or St. may also refer to:
Arts and entertainment Stanza, in poetry Suicidal Tendencies, an American heavy metal/hardcore punk band Star Trek, a science-fiction media franchise Summa Theologica, a 13th-century compendium of Catholic philosophy and theology by St. Thomas Aquinas "S.T. the Space Traveler", a 1990 episode (S8 E8 / #97) of 1983 TV series Alvin and the Chipmunks Stranger Things, a 2016–2025 Netflix sci-fi horror series Skibidi Toilet, a 2023–present YouTube animated web-series
Geography Generic terms State (polity) Strait Street, e.g. in addresses
Specific places São Tomé and Príncipe Saxony-Anhalt (ISO 3166 code DE-ST), a state of Germany ST postcode area, UK, centered around Stoke-on-Trent Split, Croatia and its surrounds, indicated with prefix ST on vehicle registration plates of Croatia Sudan (aircraft registration prefix ST; see aviation in Sudan)
Language and typography Sesotho language (ISO 639-1 language code "") or , typographic ligatures Standard Theory, in generative grammar
Law Scheduled Tribes, in India ST, the court-ordered pseudonym used in the Sudiksha Thirumalesh case
Science and technology Electronics and computing ST connector, Straight Tip optical fiber connector Seagate Technology, an American data storage company, whose hard disk drives are named with the prefix "ST-" STMicroelectronics, a worldwide manufacturer of semiconductors Atari ST, a 1985 line of personal computers Internet Stream Protocol, an experimental Internet protocol Structured text, a high-level programming language that syntactically resembles Pascal and is designed for programmable logic controllers (PLC) .st, the Internet country code top-level domain (ccTLD) for São Tomé and Príncipe
Mathematics Standard part function, a mapping from hyperreal to real numbers Such that (s.t.), a phrase preceding a condition predicate
Physics String theory, a model of subatomic structure Spherical tokamak or spherical torus (ST), a type of fusion power device Stanton number (St), relating to thermodynamics of fluid Strouhal number (St), describing oscillating flow mechanisms
Medicine ST segment, the part of an electrocardiogram connecting the QRS complex and the T wave Sulfotransferase, enzymes that catalyze the transfer of a sulfo group Heat-stable enterotoxin, secretory peptides produced by some bacterial strains, such as enterotoxigenic Escherichia coli
Units of measurement Stokes (unit) (St), a CGS unit of kinematic viscosity Stone (weight) (st.), a unit of mass used in the British Isles and other countries
Other uses in science and technology ST Engineering, a global technology, defense, and engineering group headquartered in Singapore ST, the ship prefix for a steam tug or steam trawler
Transportation companies German airline Germania (airline) (IATA airline designator "ST") ST, the railroad reporting mark for American railroad Springfield Terminal Railway (Vermont) Sound Transit, a shortened form of Central Puget Sound Regional Transit Authority in the U.S. state of Washington State Transport, a shortened form of Maharashtra State Road Transport Corporation of India Suffolk Transit, a shortened form of Suffolk County Transit, the bus system serving Suffolk County, New York, U.S. Stouffville line (ST), of the GO Transit rail network in Ontario, Canada
Other uses sine tempore, a Latin term used to indicate that a lecture will begin at the exact time; see academic quarter (class timing) Striker (association football), a position in association football Statstjänstemannaförbundet, or Swedish Union of Civil Servants, a trade union
See also ΣΤ (disambiguation) (sigma tau) STST (disambiguation) STFC (disambiguation) for uses of ST F.C.