IST
Abbreviation with 5 meanings
| Stands for | India Standard Time |
|---|---|
| Meanings | 5 |
| Categories | Units & Measurements, Transportation & Travel, Law & Legal |
IST has five meanings. The most common are India Standard Time (time zone) and Istanbul Airport (airport code); it can also stand for Irish Standard Time, Israel Standard Time and Incompetent to stand trial.
Meanings of IST at a glance
| # | IST stands for | Context |
|---|---|---|
| 1 | India Standard Time | Units & Measurements › Time Zone |
| 2 | Istanbul Airport | Transportation & Travel › Airport Code |
| 3 | Irish Standard Time | Units & Measurements › Time Zone |
| 4 | Israel Standard Time | Units & Measurements › Time Zone |
| 5 | Incompetent to stand trial | Law & Legal › Criminal Law |
1. India Standard Time
Units & Measurements · Time Zone Abbreviations
UTC+5:30, the single time zone for all of India, also used in Sri Lanka. The half-hour offset is based on the 82.5° E meridian near Mirzapur, close to the center of the country.
Example: The results will be announced at 11 a.m. IST, 05:30 UTC.
India does not observe daylight saving. Because one zone spans about 30 degrees of longitude, the sun rises nearly two hours earlier in Arunachal Pradesh than in Gujarat, and Assam's tea estates have long kept an unofficial "tea garden time" an hour ahead. IST also abbreviates Irish Standard Time and Israel Standard Time.
2. Istanbul Airport
Transportation & Travel · Airport Code Abbreviations
Turkish Airlines' hub and one of the world's busiest airports, located on the Black Sea side of Istanbul's European half. It opened in 2018, with all scheduled passenger flights moving there in April 2019.
Example: My connection at IST to Nairobi is three hours, so I'll grab breakfast in the terminal.
ICAO code LTFM. When the new airport opened, it took over the IST code from Atatürk Airport, which closed to passenger flights in an overnight operation that moved Turkish Airlines' equipment across the city. The airport is designed for eventual capacity of 200 million passengers a year. Turkish Airlines serves more countries than any other airline.
3. Irish Standard Time
Units & Measurements · Time Zone Abbreviations
Ireland's summer time, one hour ahead of UTC, used from the last Sunday in March to the last Sunday in October. In winter Ireland uses Greenwich Mean Time, so its clocks match the UK all year.
Example: Doors open at 7:30 p.m. IST for the Dublin concert.
Irish law, under the Standard Time (Amendment) Act 1971, defines standard time as UTC+1 and treats the winter GMT period as the exception, the reverse of British practice. Until 1916 Ireland used Dublin Mean Time, about 25 minutes behind Greenwich.
4. Israel Standard Time
Units & Measurements · Time Zone Abbreviations
Israel's winter time, two hours ahead of UTC. Since 2013 Israel has switched to Israel Daylight Time (IDT, UTC+3) on the Friday before the last Sunday in March and back on the last Sunday in October.
Example: Shabbat candle lighting in Jerusalem is at 4:12 p.m. IST this Friday.
Israel's daylight saving dates were long a political issue, at times tied to the Hebrew calendar so that summer time ended before Yom Kippur, until a 2013 law extended it to late October. The Palestinian territories use the same UTC+2 offset but set their own daylight saving dates.
5. Incompetent to stand trial
Law & Legal · Criminal Law Abbreviations
Finding that a defendant cannot be tried because a mental illness or intellectual disability prevents them from understanding the proceedings or assisting in their own defense. The case is suspended while the person receives treatment aimed at restoring competency.
Example: After the evaluation, the judge found him IST and committed him to the state hospital for restoration.
The standard comes from Dusky v. United States (1960): a rational and factual understanding of the proceedings and the ability to consult with a lawyer. Jackson v. Indiana (1972) bars holding someone indefinitely solely because of incompetency. Competency concerns the defendant's present condition, unlike insanity, which concerns the state of mind at the time of the crime.
Related abbreviations
More time zone abbreviations
- HST – Hawaii-Aleutian Standard Time
- ICT – Indochina Time
- IDL – International Date Line
- IRST – Iran Standard Time
- JST – Japan Standard Time
- KST – Korea Standard Time
- LMT – Local mean time
- LT – Local time
See all 64 time zone abbreviations →
More airport code abbreviations
- IAD – Washington Dulles International Airport
- IAH – George Bush Intercontinental Airport
- ICN – Incheon International Airport
- IND – Indianapolis International Airport
- JAX – Jacksonville International Airport
- JED – King Abdulaziz International Airport
- JFK – John F. Kennedy International Airport
- JNB – O. R. Tambo International Airport
See all 170 airport code abbreviations →
This entry is for general education and is not legal advice. Abbreviation use varies between institutions; always confirm in context.