Drones. The word itself has its fans (particularly in the news media) and its detractors (including the UN under-secretary general for peacekeeping). So does the use of drones for killing people.

But when you start to examine the term and its many variations, the drones lexicon appears to obscure rather than clarify.

This should probably come as no surprise in an age when terms like "extraordinary rendition" (kidnapping) and "enhanced interrogation" (torture) are now part of the political language.

Here's a short glossary of words to help you understand, or misunderstand, the debate about drones.

Unmanned aerial vehicle: UAV is the military's preferred term for drones. Unmanned combat air vehicle is sometimes used to differentiate the ones that are armed.

According to the Congressional Research Service, the U.S. military has about 7,500 drones, of which about 375 are armed. At the UN, which has been critical of drone programs, the word itself may become almost taboo.

This week, for example, the under-secretary general for peacekeeping operations, Herve Ladsous, responded when asked about UN plans to use drones for surveillance in the Democratic Republic of Congo: "I would not use the word drones."

He told the reporters that he, too, preferred "unmanned aerial vehicles."

Predator: A drone built by General Atomics, in use since 1995, has some models that have been armed since early 2001. The name suggests the target is not human but prey, John Sifton of Human Rights Watch notes.Predator is similarly used in writing about crime.

A U.S. Air Force MQ-9 Reaper unmanned aerial vehicle prepares to take off from Wheeler-Sack Army Airfield at Fort Drum, N.Y. Oct. 18, 2011. (Staff Sgt. Ricky Best/USAF/Reuters)

Reaper: A later, larger version of the Predator, also built by General Atomics, it has been in operation since 2007.

Sifton observes that its name is "a moniker implying that the United States was fate itself, cutting down enemies who were destined to die."

Hellfire missile: Predators and Reapers fire AGM-114 Hellfire missiles at their targets. Sifton says that the 163 centimetre missiles' name invokes "the punishment of the afterlife, adding to a sense of righteousness."

Naugahyde Barcalounger: That's what the pilots call the cockpit seat in the command centre at Creech Air Force Base in Nevada, which operates the drones flying over Afghanistan and elsewhere.

When pilots at the ground control station who have fired at a target see a hit on one of their screens, they call out "Splash!," according to the Los Angeles Times.

Bugsplat: That is the name of U.S. Defence Department software for calculating and reducing collateral damage (dead civilians) resulting from airstrikes.

Family members surround caskets during a mass funeral in Miranshah, Pakistan, June 16, 2011. Local residents say the dead were killed in a drone attack a day earlier. (Haji Mujtaba/Reuters)

Bugsplat was first used in the Iraq war in 2003. Back then, officials told the Washington Post that it would, "more precisely model potential damage by a particular type and size of bomb dropped by a particular aircraft flying at a given altitude." The CIA also uses Bugsplat.

Signature strike: This is the U.S. term for an intended lethal strike against an individual whose identity may be unknown but whose behaviour fits a pattern that suggests to the CIA or the U.S. military that this person is involved in militant or terrorist activities.

President George W. Bush first authorized signature strikes by drones in Pakistan in 2008.

The number of these strikes has been dropping in Pakistan since 2010. In 2012 President Barack Obama authorized their use in Yemen.

The New York Times reports that the White House "counts all military-age males in a strike zone as combatants, according to several administration officials." The CIA also uses the term "crowd killing" for signature strikes.

Targeted killing: This refers to the assassination of a known individual. Others used to call this extrajudicial execution.

John Brennan, now President Obama's nominee for CIA director, has been the chief author of Obama's targeted killing strategy.

Targets have included U.S.-born Anwar al-Awlaki, an al-Qaeda propagandist who was killed by a drone strike in Yemen in 2011. A targeted drone strike in 2009 killed Baitullah Mehsud, the Pakistani Taliban chief believed responsible for the assassination of former Prime Minister Benazir Bhutto.

Drone attacks had missed Mehsud at least 16 times in the preceding 14 months, killing 280 to 410 people in those attacks, based on estimates by the New America Foundation, a Washington think tank.

Disposition matrix: This is a database overseen by Brennan that augments "separate but overlapping kill lists" maintained by the CIA and the military. It also includes "biographies, locations, known associates and affiliated organizations" as well as "strategies for taking targets down, including extradition requests, capture operations and drone patrols," according to The Washington Post, which first reported the database's name.

Imminent threats: At his confirmation hearing Thursday, Brennan said that the administration uses drone strikes only as a deterrent against imminent terrorist threats to the U.S. In order to target Mehsud in Pakistan, that had to be stretched to include U.S. troops.

The Department of Justice white paper leaked to NBC News this week explains how the definition of imminent is being expanded: "The condition that an operational leader present an 'imminent' threat of violent attack against the United States does not require the United States to have clear evidence that a specific attack on U.S. persons and interests will take place in the immediate future."

Jameel Jaffer of the American Civil Liberties Union told NBC News that the Obama policy recognizes "some limits on the authority it sets out, but the limits are elastic and vaguely defined, and it's easy to see how they could be manipulated."