SIL, Sil and sil may refer to:
In organizations:
- State Informatics Limited (SIL) is a Systems Integrator in Mauritius and a leading ICT company in Africa.
- SIL International, a global Christian non-profit organization that studies lesser-known languages.
- SIL, formerly the American Stock Exchange ticker symbol for Apex Silver Mines.
- Societas Internationalis Limnologiae, former name for the International Society of Limnology.
- Society for Individual Liberty, later part of the International Society for Individual Liberty.
- Scooters India Limited, formed when the Indian government purchased Lambretta.
- Southwest International League, a defunct American minor league baseball league.
In science and technology:
- Solid immersion lens, a device usually used in optical microscopy.
- Standard Interchange Language, a language standard used for the information exchange between software.
- Software-in-the-Loop, a method used in regression testing.
- Sil, a vector drawing program for the Xerox Star computer system.
- SIL, an alternate symbol for the human gene STIL.
- Surge impedance loading, a physical property of electrical transmission lines.
- Squamous intraepithelial lesion, abnormal tissue situated within a squamous epithelium.
- Safety Integrity Level, a measurement of performance required for a Safety Instrumented Function.
- Speech Interference Level, an acoustical parameter.
- Stable Isotope Labelling e.g. SILAC.
In fiction:
- Sil (Doctor Who), a villain from the British science-fiction series Doctor Who.
- Sil, a character in the film Species.
- Silvio Dante, a character on The Sopranos.
In people:
- Narasingha Sil, historian.
- Sil Campusano, a former Major League Baseball player.
- Sil Austin, a jazz saxophonist.
- Sil, a member of the Dutch rap-metal band Urban Dance Squad.
- Sil, Minor Lastname in Poland 35-50 persons
Other uses:
- Sil (river), a river in Galicia, Spain.
- Sile (river), also called the "Sil", in Italy.
- SIL code, a three-letter language code used in SIL International's Ethnologue.
- sil, the ISO 639-3 language code for Tumulung Sisaala.
- South Island Line, a plan of MTR Hong Kong.
- Safety Integrity Level, a measure of performance required for a safety instrumented system.
- Silverstone Circuit, an English motor racing circuit.
- Son-in-law or sister-in-law, in on-line and text messaging usage.
- Sing it Loud, an American pop rock band.
- Silence-Lotto, the UCI code for the professional road bicycle racing team.
- Nissan Silvia, short/slang name for the Nissan Silvia series.