A procedure whereby criminal suspects are sent for interrogation from one country to a second country, where less strict laws governing interrogation apply.
I'd like to tread carefully here and make it clear that this article is an examination of 'extraordinary rendition' from a linguistic point of view, not a political diatribe. It's difficult to discuss the phrase without referring to politics and this may cause those with strong views on US military policy one way or the other to assume bias on my part. I'll try, where referring to political events, to attempt to avoid opinion and stick to the facts.
The phrase became widely known during 2005 when newspaper articles began drawing attention to the fact the US Government was sending terrorist suspects, previously held in the USA, to countries that have less stringent laws against torture, and interrogating them there. It may have been used internally within US government circles before then, although there aren't any known hearsay reports of it prior to Sept 2001.
While accepting that such suspects have been relocated to other countries from the US, the US Government has made repeated high-level denials that this was for any suspicious reasons. In January 2005, US President Bush, in an interview with the New York Times, said: "torture is never acceptable, nor do we hand over people to countries that do torture.". That's probably enough of the political background to get on with discussing the phrase itself. This has been with us since the 1980s and the first documented use is in Cherif Bassiouni's International Extradition: United States Law and Practice, 1983:
"The United States increasingly resorts to extraordinary rendition devices, including abduction, thus circumventing traditional extradition processes."
Rendition, in this context, means handing over. It has the same root as surrender. Extraordinary means unusual, literally 'outside the ordinary'.
Put together they don't appear to add up to much, and really that's the point. The phrase is in the long and ignoble tradition of doublespeak - appearing to communicate but in fact using bland or inoffensive language to draw a veil over real meaning.
Euphemisms of all sorts are coined to avoid talking directly about things we find uncomfortable. War and death have to rank highly on that list so it's no big surprise that the military wings of governments are especially good at this.
It's not new, in the Second Boer War, 1899 - 1902, the British Government needed somewhere to house refugees whose homes they had destroyed. Thus was born the term 'concentration camps', which on first hearing must have sounded almost cosy. The First World War gave us 'shell-shock' and WWII 'comfort women'. More recently, we've had 'friendly fire', 'ethnic cleansing' and 'collateral damage', amongst others.
Now 'extraordinary rendition' can be added. The words have a literal meaning that we can easily understand, but the phrase itself conveys no useful meaning when heard out of context - which is, of course, exactly the intention.