On Monday, U.S. forces stepped up a campaign of airstrikes in Iraq, targeting a fearsome

four-letter terrorist organization that's become synonymous with videotaped beheadings. It's all part of a military strategy that follows President Obama's recent pledge to "degrade, and ultimately destroy, ISIL through a comprehensive and sustained counter-terrorism strategy."

But you might have wondered why the commander-in-chief keeps referring to the organization as ISIL?

More to the point, is ISIL the same as ISIS, which is what almost everyone else is calling the group? Good question.

How It All Started

The idea for ISIS was hatched more than two decades ago by Jordanian fighter and Sunni extremist Abu Musab al-Zarqawi under the name Jama'at al-Tawhid wal-Jihad, which was soon commonly referred to as Al-Qaeda in Iraq. By 2004, he had allied himself with Osama Bin Laden and Al Qaeda proper, targeting coalition forces using IEDs, suicide bombers and hostage executions.

When Things Changed

After Al-Zarqawi's death in 2006 during a U.S. airstrike, new leader Abu Ayyub al-Masri renamed the group the Islamic State of Iraq. When Masri was killed in 2010, Abu Bakr al-Baghdadi rose to power and changed the name once again in April 2013 to the Islamic State of Iraq and the Levant, a nod to the group's incursion into a new region: Syria. The "L" is also, of course, what's referred to in the term ISIL.

Why ISIS?

In Arabic, the group's name translates to Al-Dawla Al-Islamiya fi al Iraq wa al-Sham. (Al-Sham is a reference to Syria.) That name alludes to the concept of a larger Islamic state, or Caliphate, the group seeks to create, which would reach from Turkey to Syria and Egypt

and include parts of Lebanon, Israel, Jordan and the Palestinian territories.

Why Won't The President Use The Name?

According to the UK's Independent, President Obama has been reluctant to use the phrase ISIS because of the "S" that stands for Syria and any talk of attacking the terrorists in that country would look odd after the White House refused to send U.S. troops to help intervene in the Syrian civil war.

So Why ISIL?

"We’re moving ahead with our strategy to degrade and ultimately destroy this terrorist organization." —Obama on ISIL: http://t.co/mpaMGYgjQ0

— The White House (@WhiteHouse) September 14, 2014

The term the president used 25 times in last week's address refers to The Islamic State of Iraq and the Levant, which refers to the larger caliphate that the terrorists are trying to establish, making the threat seem that much more serious and widespread.

Does It Matter Which One You Use?

In the end, they mean the same thing, according to Daniel Pipes, president of the Middle East Forum. "One refers to a state, the other has an archaic ring," he wrote recently. "For reasons unknown to me, the executive branch of the U.S. government adopted the ISIL nomenclature and its staff generally use this term, even though members of Congress, the media, and specialists (including me) generally prefer ISIS."