TR

TR or tr may stand for:

People

• Trent Reznor, American singer and musician
• Theodore Roosevelt, the 26th president of the United States
  • The USS Theodore Roosevelt (CVN-71), a Nimitz-class aircraft carrier

In official codes

• Tiger Airways IATA code (since September 2003)
• Tomahawk Railway, reporting mark
• Transbrasil airline IATA code (to 2001)
• Turkey, the ISO 3166-1 alpha-2 country code
  • .tr, the country code top level domain (ccTLD) for Turkey
• tr, the code for the Turkish language, in ISO 639 alpha-1
• TR postcode area, UK postal code for the Truro area
• TR-1, Tactical Reconnaissance vwersion of the Lockheed U-2
• Technical Report, a type of ISO document

In engineering, science and computing

• the table row HTML element
• tr, a Unix program
• trace (linear algebra), the sum of the main diagonal elements of a square matrix in linear algebra
• The digraph tr
• Transistor
• an abbreviation for the trityl (triphenylmethane) group in chemistry

In medicine

• Thyroid hormone receptor, a nuclear receptor that is activated by binding thyroid hormone
• Tubal reversal, a microsurgery to open and reconnect the fallopian tubes after a tubal ligation procedure
• Tricuspid regurgitation, a leakage of blood within the heart

In music

• Trill
• TR-808, TR-909 etc., 1980s Roland drum machines (for "Transistor Rhythm")
• Korg TR, a music workstation synthesizer

In games

• Currency in online game TalesRunner
• The Terran Republic, a faction in the game PlanetSide
• Tomb Raider

In transportation

• Talyllyn Railway, the world's first preserved heritage railway in Wales, United Kingdom
• Sports cars by the Triumph Motor Company, e.g. Triumph TR2
• Thai Rung Union Car
• NZR TR class locomotive
• Toronto Rocket, Canada, subway train
• Tr., abbreviation of "trail" in street names

Places

• Travelers Rest, South Carolina, US

Other uses

• Training routines (Scientology)
• Thomson Reuters, a global company