linguistic:translation
Origin and usage

The Oxford English Dictionary defines conspiracy theory as "the theory that an event or phenomenon occurs as a result of a conspiracy between interested parties; spec. a belief that some covert but influential agency (typically political in motivation and oppressive in intent) is responsible for an unexplained event". It cites a 1909 article in The American Historical Review as the earliest usage example, although it also appeared in print for several decades before.

The earliest known usage was by the American author Charles Astor Bristed, in a letter to the editor published in The New York Times on January 11, 1863. He used it to refer to claims that British aristocrats were intentionally weakening the United States during the American Civil War in order to advance their financial interests.

England has had quite enough to do in Europe and Asia, without going out of her way to meddle with America. It was a physical and moral impossibility that she could be carrying on a gigantic conspiracy against us. But our masses, having only a rough general knowledge of foreign affairs, and not unnaturally somewhat exaggerating the space which we occupy in the world's eye, do not appreciate the complications which rendered such a conspiracy impossible. They only look at the sudden right-about-face movement of the English Press and public, which is most readily accounted for on the conspiracy theory.

The term is also used as a way to discredit dissenting analyses. Robert Blaskiewicz comments that examples of the term were used as early as the nineteenth century and states that its usage has always been derogatory. According to a study by Andrew McKenzie-McHarg, in contrast, in the nineteenth century the term conspiracy theory simply "suggests a plausible postulate of a conspiracy" and "did not, at this stage, carry any connotations, either negative or positive", though sometimes a postulate so-labeled was criticized. The author and activist George Monbiot argued that the terms "conspiracy theory" and "conspiracy theorist" are misleading, as conspiracies truly exist and theories are "rational explanations subject to disproof". Instead, he proposed the terms "conspiracy fiction" and "conspiracy fantasist".