Sir (disambiguation)

Sir is a respectful form of address for a man, and a formal title used in the United Kingdom for knights and baronets.

Look up SIR, Sir, or sir in Wiktionary, the free dictionary.

Sir, SIR or SiR may also refer to:

Places

Sir (A Series of Unfortunate Events), a fictional character in A Series of Unfortunate Events
Sir, or Mark Thackeray, the title character of the 1967 film To Sir, with Love

Security Industry Registry, a corporate service provided by the New South Wales Police Force
Sigma Iota Rho, a collegiate honour society for international studies
Singapore Infantry Regiment, the main formation of the Singapore Army
Society of Interventional Radiology, an American organization of health professionals
Sons In Retirement, a fraternal organization of retired men

SIR model, a compartmental model of the progress of an epidemic
Secondary image registration, a type of passive autofocus in cameras
Sequential Importance Resampling, a particle filtering algorithm
Serial Infrared, the physical layer of the IrDA standard for data transmission
Short interest ratio, a metric signalling prevailing investors' sentiment
Signal-to-interference ratio, the ratio of useful signal versus co-channel interference received
Silent information regulator protein involved in regulating gene expression
Supplemental inflatable restraint or airbag, a vehicle safety device

Siantar railway station, Pematang Siantar, Indonesia
South Indian Railway, an early Indian railway company
Staten Island Railway, rapid transit line in the borough of Staten Island, New York, United States
Surrey Iron Railway, a horse-drawn plateway that linked the former Surrey towns of Wandsworth and Croydon
Sion Airport, the airport in Sion, Switzerland whose IATA code is SIR

Sirene (Sir in Serbian), a type of cheese
Statutory Invention Registration, a publication of an invention by the United States Patent and Trademark Office
Special Intensive Revision, an exercise undertaken by the Election Commission of India to prepare the voters list