People are already arguing over whether the Austin bombings — in which a 23-year-old white man from Texas is suspected of having carried out a spate of deadly bombings in and around Austin in recent days — should be labeled as "terrorist attacks."

But the debate over which acts should and shouldn't be labeled "terrorism" is nothing new. Historian J. Bowyer Bell once said: "Tell me what you think about terrorism, and I will tell you who you are."

If and how you apply the terrorism label depends on who you are and what your purpose is. For example, many in the American Muslim community object that only events linked to "radical Islam" are labeled as terrorism by politicians and the media — while attacks by white supremacists and neo-Nazis, such as the 2015 mass shooting at a historic black church in Charleston, South Carolina, aren't.

As a result, it is often said that there is "no definition of terrorism." But that's not quite accurate. What people mean is that there is no one standard definition of terrorism that everyone agrees on. It's not that we don't have a definition for terrorism; it's that we have too many.

To help understand what people are actually saying when they use the word "terrorism," it's useful to think about terrorism as three different things: a tactic, a legal term, and a political label. Understanding each of these ways the "terrorism" label is used will help you understand why different people call different things "terrorism" — and why it's such a controversial, but important, term.

How analysts think: terrorism as a tactic

Terrorism scholars and analysts primarily view terrorism as one tactic among many. They see terrorist organizations as groups that are trying to accomplishing specific goals, whether those goals are establishing a caliphate and bringing about the apocalypse (like ISIS), gaining political and territorial independence for the group they claim to represent (like the Basque separatists in Spain), or persuading governments and corporations to act more responsibly toward animals or the environment (like the Earth Liberation Front).

Thinking of terrorism as a tactic helps us think more critically about these groups and how to deal with them. Because although we often talk about "terrorist groups," the reality is that most of these organizations use a variety of tactics throughout their lifespan depending on their goals and capabilities at the moment.

For instance, calling ISIS a "terrorist" group ignores the fact that in Iraq and Syria, ISIS has used more conventional military tactics — massing forces, launching complex operations, and taking and holding territory — in addition to carrying out terror attacks. ISIS also functioned as a government, providing law and order, repairing roads, keeping the electricity on, and selecting textbooks for schools.

Treating ISIS as merely a "terrorist" organization fails to understand the way it operates, what its goals are, and how it maintains support and financing — all things that are critical to figuring out how it can be defeated.

Analysts also try to define terrorism along very specific lines in order to separate it from other kinds of violence, such as legitimate acts of war. This can be confusing to non-experts (and sometimes experts, too). For example, many scholarly definitions of terrorism do not consider attacks against military targets in a combat zone to be terrorism — only attacks against civilians (or "noncombatants").

But what exactly is a "combat zone" when we're talking about the fight against international terrorist groups? For groups like al-Qaeda and ISIS, the whole world is a combat zone. And who exactly is a "noncombatant"? If ISIS detonates a car bomb that kills US military advisers on the ground in Iraq, is that terrorism or an act of war?

Similarly, many scholarly definitions of terrorism require that the attack have an explicit political motive. Which means that even a series of bombings that killed and injured numerous of people may not be considered an act of "terrorism" by scholars if it turns out that the perpetrator had no clear political motive.

These distinctions explain why you might hear an analyst on the news say that a particular attack that was "not terrorism" even though it seems to you and many others to be a clear act of terrorism. The analyst is not saying that the attack was justified or that it wasn't horrific, just that it doesn't classify as "terrorism" as he or she happens to define it.

How law enforcement thinks: terrorism as a legal term

On December 4, 2015, the FBI announced that it was officially investigating the San Bernardino shooting as "an act of terrorism." However, this came only one day after the same FBI official, when asked whether the attack was terrorism, said, "It would be irresponsible and premature for me to call this terrorism. The FBI defines terrorism very specifically, and that is the big question for us, what is the motivation for this."

So what gives? What's the big deal with not wanting to call it "terrorism" when the FBI clearly was already thinking it was?

The answer has a lot to do with the fact that the FBI is a law enforcement organization and is part of the US Department of Justice. The FBI's primary job is to investigate crimes with the goal of bringing the perpetrators to justice — in other words, to prosecute criminals in a court of law. This means the FBI's understanding of what constitutes "terrorism" has much less to do with how it views the circumstances of an attack, and much more to do with whether or not the facts of the case meet the very specific legal criteria used to prosecute someone on terrorism charges.

Under federal law, "international terrorism" means activities that:

Involve violent acts or acts dangerous to human life that violate federal or state law

Appear to be intended (i) to intimidate or coerce a civilian population; (ii) to influence the policy of a government by intimidation or coercion; or (iii) to affect the conduct of a government by mass destruction, assassination, or kidnapping

Occur primarily outside the territorial jurisdiction of the US, or transcend national boundaries in terms of the means by which they are accomplished, the persons they appear intended to intimidate or coerce, or the locale in which their perpetrators operate or seek asylum

"Domestic terrorism" means activities that:

Involve acts dangerous to human life that violate federal or state law

Appear intended (i) to intimidate or coerce a civilian population; (ii) to influence the policy of a government by intimidation or coercion; or (iii) to affect the conduct of a government by mass destruction, assassination, or kidnapping

Occur primarily within the territorial jurisdiction of the US

And 18 USC § 2332b defines the term "federal crime of terrorism" as an offense that:

Is calculated to influence or affect the conduct of government by intimidation or coercion, or to retaliate against government conduct

Is a violation of one of several listed statutes, including § 930(c) (relating to killing or attempted killing during an attack on a federal facility with a dangerous weapon); and § 1114 (relating to killing or attempted killing of officers and employees of the US)

These are the kinds of criteria the FBI is concerned with when making the determination of whether a specific act constitutes "terrorism." This is why the bureau is so careful not to call something terrorism right away. Whether you and I (or even individual FBI agents) personally think an attack is terrorism doesn't really matter — what matters is whether the FBI thinks it can make a case for prosecuting the perpetrator for terrorism in a court of law.

How politicians and pundits think: terrorism as a bad word

Renowned terrorism scholar Bruce Hoffman writes, "On one point, at least, everyone agrees: ‘Terrorism' is a pejorative term. It is a word with intrinsically negative connotations that is generally applied to one’s enemies and opponents."

He explains:

"[T]he decision to call someone or label some organization ‘terrorist’ becomes almost unavoidably subjective, depending largely on whether one sympathizes with or opposes the person/group/cause concerned. If one identifies with the victim of the violence, for example, then the act is terrorism. If, however, one identifies with the perpetrator, the violent act is regarded in a more sympathetic, if not positive (or, at the worst, ambivalent) light, and it is not terrorism."

Politicians often apply the word "terrorism" to the actions of individuals and groups they see as opponents and enemies in order to delegitimize and demonize them, to incite fear and convince a population to support controversial government actions, and to garner support by promoting an us-versus-them narrative. George W. Bush invoked terrorism and 9/11 when naming Iran, Iraq, and North Korea as members of an "axis of evil" in his 2002 State of the Union address, and Syrian President Bashar al-Assad and Russian President Vladimir Putin justify their bombing of the Syrian opposition in the name of defeating terrorism.

The US State Department's list of foreign terrorist organizations is often portrayed as some kind of exhaustive, authoritative list of terrorist groups around the world, but the truth is that which groups get included on the list and which get excluded is a largely political determination, not an analytical one.

Groups that may very well engage in the same types of activities as groups on the list have been consciously left off the list for political reasons — out of fear of offending a country we don't want to offend, or because the group is on our side, is being trained or supported by us or our friends, or is pursuing goals that we find to be in line with our interests.

There's an old cliché that everyone who studies terrorism has heard a million times and despises: "One man's terrorist is another man's freedom fighter." It's supposed to convey the idea that people are inconsistent in how they define terrorism and tend to eschew the word when the person or group in question is on their side.

But just because it's a cliché people are tired of hearing doesn't mean it's not true.