Terrorism: Etymology :: Although the term is often used imprecisely, there have been many attempts by various law enforcement agencies and public organizations to develop more precise working definitions of terrorism ... Like all political ideas, the meaning of the term "terrorism" has evolved in response to circumstances. The words "terrorism" and "terror" originally referred to methods employed by regimes to control their own populations through fear, a tactic seen in totalitarian regimes such as Nazi Germany and Soviet Russia. The term "terrorism" comes from the French word terrorisme, which is based on the Latin language verbs terrere (to frighten) and deterrere (to frighten from). It dates to 1795 when it was used to describe the actions of the Jacobin Club in their rule of post-Revolutionary France, the so-called "Reign of Terror". Jacobins are rumored to have coined the term "terrorists" to refer to themselves. Acts described as Jacobin Club "terrorism" were mostly cases of arrest or execution of opponents as a means of coercing compliance in the general public.
Up until comparatively recently, people who would now be known as "terrorists" were called "incendiaries" (due to the fact that they started fires and set off incendiary devices) ... In response to the September 11, 2001 attacks, political leaders from Europe, North America, Asia, and the Middle East have placed the phenomenon of terrorism within the context of a global struggle against systems of government perceived by those accused of using terrorist tactics as harmful to their interests. The European Union includes in its 2004 definition of "terrorism" the aim of "destabilising or destroying the fundamental political, constitutional, economic or social structures of a country."
Terrorism: State sponsors :: Some states have been accused of sponsoring terrorist actions in foreign countries, as an alternative to carrying them out directly and risking an open declaration of war. State-sponsored terrorism is widely denounced by the international community. When states do provide funding for groups considered by some to be terrorist, they rarely acknowledge them as such ... Noam Chomsky, senior scholar with the Institute for Policy Studies, says that "the U.S. itself is a leading terrorist state." After President Bush declared a "War on Terrorism," Chomsky stated:
The U.S. is officially committed to what is called “low–intensity warfare.” [...] If you read the definition of low–intensity conflict in army manuals and compare it with official definitions of “terrorism” in army manuals, or the U.S. Code, you find they’re almost the same. 
Terrorism: Global trends :: Since 1968, the U.S. State Department has tallied deaths due to terrorism. In 1985, it counted 816 deaths, the highest annual toll until then. The deaths decreased since the late 1980s, then rose to 3,295 in 2001, mainly as a result of the September 11, 2001 attacks. In 2003, more than 1,000 people died as a result of terrorist acts. Many of these deaths resulted from suicide bombings in Chechnya, Iraq, India and Israel. It does not tally victims of state terrorism. Data from the Terrorism Knowledge Base showed a similar decline since the 1980s, especially in Western Europe. On the other hand, Asia experienced an increase in international terrorist attacks. Other regions experienced less consistent patterns over time. From 1991 to 2003, there was a consistent increase in the number of casualties from international terrorist attacks in Asia, but few other consistent trends in casualties from international terrorist attacks. Three different regions had, in three different years, a few attacks with a large number of casualties. Statistically, the distribution of the severity of terrorist attacks follows a power law, much like that for wars and also natural disasters like earthquakes, floods and forest fires.
From old wars to new wars and global terrorism :: (Abstract) Even before 9/11 there were claims that the nature of war had changed fundamentally. The 9/11 attacks created an urgent need to understand contemporary wars and their relationship to older conventional and terrorist wars, both of which exhibit remarkable regularities. The frequency-intensity distribution of fatalities in "old wars", 1816-1980, is a power-law with exponent 1.80. Global terrorist attacks, 1968-present, also follow a power-law with exponent 1.71 for G7 countries and 2.5 for non-G7 countries. Here we analyze two ongoing, high-profile wars on opposite sides of the globe - Colombia and Iraq. Our analysis uses our own unique dataset for killings and injuries in Colombia, plus publicly available data for civilians killed in Iraq. We show strong evidence for power-law behavior within each war. Despite substantial differences in contexts and data coverage, the power-law coefficients for both wars are tending toward 2.5, which is a value characteristic of non-G7 terrorism as opposed to old wars. We propose a plausible yet analytically-solvable model of modern insurgent warfare, which can explain these observations.
Low intensity conflict :: Low-Intensity Operations is a military term for the deployment and use of troops in situations other than war. Generally these operations are against non-state adversaries and are given terms like counter-insurgency, anti-subversion, and peacekeeping. Some, depending on political alignment, view LIC as a form of terrorism. The term "low intensity operations" appears to have originated with General Sir Frank Kitson.
Low-intensity conflict is defined by the US Joint Chiefs of Staff (as promulgated in the US Army Field Manual 100-20) as:
... a political-military confrontation between contending states or groups below conventional war and above the routine, peaceful competition among states. It frequently involves protracted struggles of competing principles and ideologies. Low-intensity conflict ranges from subversion to the use of the armed forces. It is waged by a combination of means, employing political, economic, informational, and military instruments. Low-intensity conflicts are often localized, generally in the Third World, but contain regional and global security implications.