The term political radicalism (or simply, in political science, radicalism) denotes political principles focused on altering social structures through revolutionary means and changing value systems in fundamental ways. Derived from the Latin radix (root), the denotation of radical has changed since its eighteenth-century coinage to comprehend the entire political spectrum—yet retains the "change at the root" connotation fundamental to revolutionary societal change. Historically, radicalism has referred exclusively to the radical left (under the single category of far-left politics) and rarely incorporating far-right politics, though these may have revolutionary elements; the prominent exception is in the United States where some consider radicalism to include both political extremes of the radical left and the radical right. In traditional labels of the spectrum of political thought, the opposite of radical on the "right" of the political spectrum is termed reactionary.