The full name of Adolf Hitler's party was Nationalsozialistische Deutsche Arbeiterpartei (National Socialist German Workers' Party; NSDAP). The shorthand Nazi was formed from the first two syllables of the German pronunciation of the word "national".

As MPs debated whether to commit Britain to air strikes in Syria, the debate surrounding how to refer to Isis continued.

Downing Street announced on Wednesday that David Cameron and other government ministers would start using the word "Daesh" when referring to the terror group.

If it were up to the militants themselves, the world would refer to them as "Islamic State" in recognition of the caliphate they have declared, but David Cameron asked the BBC to stop using the term in June.

The British and US Governments use the term Isil, while the name Isis is more commonly seen and is favoured by The Independent.

Last year, the French government announced their decision to use the Arabic-derived term "Daesh" to replace their previous name, EIIL ( L'Etat Islamique en Irak et en Syrie).

The four competing names are among a handful of those used by Isis, which emerged in 1999 when it was established by Abu Musab al-Zarqawi, a Jordanian militant who allegedly ran a terror training camp and orchestrated bombings and beheadings in Iraq.

His group was initially known as Jama'at al-Tawhid wal-Jihad, before changing to the simpler al-Qaeda in Iraq (AQI) after pledging allegiance to Osama bin Laden's network in October 2004.

Since then, the group has operated under numerous guises until its current leader, Abu Bakr al-Baghdadi, declared it the Islamic State in Iraq (Isi) in 2006, adding the "and al-Sham" to make "Isis" in 2013.

So what do the different names mean?


Islamic State (IS)
In June 2014, the militants announced they were dropping the last two letters of their acronym and instead should be referred to as the Islamic State in recognition of their self-declared caliphate.


The Islamic State of Iraq and Syria (ISIS)
The original name for the group in Arabic was Al-Dawla Al-Islamiya fi al-Iraq wa al-Sham.

The first three words translate to the Islamic State of Iraq, while "al-Sham" refers to Syria and the wider surrounding area.

The group's stated goal is to restore an Islamic state, or caliphate, in the entire region.

However, the acronym poses an issue for many companies and brands around the world already using the name Isis, often named after the ancient Egyptian goddess of the same name.

The Islamic State of Iraq and the Levant (ISIL)
The undefined region around Syria is historically referred to as the Levant (an archaic French phrase for the "lands of the rising sun), including modern-day Syria, Lebanon, Israel, Palestine and Jordan.

Until Wednesday, this was the main name used by British Government ministers to refer to Isis.

The Obama administration has said it uses the acronym Isil as it believes the word "Levant" to be a more accurate translation from the Arabic name.


Daesh
Daesh, sometimes spelled DAIISH or Da'Esh, is short for Dawlat al-Islamiyah f'al-Iraq wa al-Sham.

Many Arabic-speaking media organisations refer to the group as such.

Maajid Nawaz, chairman of the anti-extremist Quilliam foundation, described it as an "ignorant, embarassing and obsessively distracting political trend".

He argues Arabic-speakers use the word Daesh because it is "merely the exact Arabic equivalent to the English acronym Isis or the more technically accurate Isil".

He adds: "Daesh does not mean anything else in Arabic. It is merely the Arabic acronym for Isil."

ISIS frequently uses its online magazine Dabiq to set out its vision. The title of the magazine is no accident -- Dabiq is a town in northern Syria currently held by ISIS where, according to Islamic prophecy, the armies of Rome will mass to meet the armies of Islam.

Prophecy is critical to ISIS, which accepts the word of the Prophet and the hadith, or sayings, attributed to him literally and without question. Prophecy provides ISIS with the glue of theological certainty. And according to those prophecies, the Islamic armies will ultimately conquer Jerusalem and Rome.

ISIS ideologues constantly cite the Quran in shaping the group's vision. Hundreds of the group's statements, audio and video messages, carry copious references to the words of the Prophet. No matter that the majority of Muslims -- even many jihadists - see ISIS' interpretations of the Quran and the hadith as manipulations or distortions.

The revival of the caliphate is the launching pad for a global battlefield. No caliph can govern without pursuing offensive jihad, and that jihad will continue, as Dabiq put it, until "the shade of the blessed flag will expand until it covers all eastern and western extents of the Earth."

That jihad has already begun -- and in the process ISIS supporters point to the prophecy that declares: "There will come a time when three armies of Islam shall simultaneously rise, one in the Levant, one in Yemen and one in Iraq."

It is powerful motivation to ISIS supporters, and it's also a message to Muslims: The end of times is at hand, and if you want to be a true Muslim, on the right side of history, you had better join us.

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ISIS does not recognize the borders of nation states that make up the modern world nor the idea of a democratic state or citizenship. It sees these as man-made creations at odds with the notion of a caliphate. So it frequently celebrates its ability to defy the "Sykes-Picot line," the colonial-era border that divides Iraq and Syria.

It even produced a video entitled "The End of Sykes-Picot" in which a voice-over declared: "This is not the first border we will break. Inshallah, we break other borders also, but we start with this one."

ISIS has created provinces -- wilayat -- that bear no resemblance to existing states. Baghdadi himself has put the destruction of borders front and center of ISIS' goals. "The Islamic State does not recognize synthetic borders, nor any citizenship besides Islam," he declared in 2012.

ISIS sees itself as coming to the rescue of Muslim minorities the world over. "We won't enjoy life until we liberate the Muslims everywhere, and until we retrieve Al-Quds (Jerusalem) and regain Al-Andalus (Andalucia in Spain), and conquer Rome," Adnani said in 2013.

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ISIS' ideology as a militant Sunni group is also fixated with purifying Islam, and that means eradicating Shia Muslims or expelling them from the caliphate. It has already shown extreme cruelty toward Shiites -- most notably slaughtering more than 1,500 Iraqi air force cadets in Tikrit in June 2014.

This visceral anti-Shia hatred was promoted by Zarqawi, who wanted to foment civil war in Iraq between the Sunni and Shia. He and his successors regard Shiites as "innovators" -- those who dare to interpret the Quran and therefore deny its perfection.

"The danger from the Shi'a ... is greater and their damage worse and more destructive to the (Islamic) nation than the Americans," Zarqawi once said.