Short answers, pulled from the story.
The word terrorism emerged from the French Revolution of the late 1790s to describe the actions of the Jacobin Club during the Reign of Terror. Jacobin leader Maximilien Robespierre declared that terror was nothing other than justice, prompt and severe.
The United States Code defines terrorism as acts intended to intimidate civilians or influence government policy through coercion. No universal legal definition exists today despite over one hundred different definitions proposed by scholars and governments.
The Irish Republican Brotherhood founded in 1858 initiated the Fenian dynamite campaign in 1881 using timed explosives to sow fear within metropolitan Britain. This organization developed ideas such as targeted killing of leaders of oppression alongside early anarchist groups like Narodnaya Volya formed in Russia in 1878.
The Global Terrorism Database recorded more than sixty-one thousand incidents of non-state terrorism resulting in at least one hundred forty thousand deaths between 2000 and 2014. Religious extremism has overtaken national separatism as the main driver of terrorist attacks around the world since September 11.
Former British Prime Minister Margaret Thatcher famously called publicity the oxygen of terrorism connecting it closely to media exposure. Walter Laqueur wrote that terrorism was always to a large extent about public relations and propaganda with Propaganda by Deed serving as the slogan in the nineteenth century.