auto-da-fe (n.)

"sentence passed by the Inquisition" (plural autos-da-fé), 1723, from Portuguese auto-da-fé "judicial sentence, act of the faith," especially the public burning of a heretic, from Latin actus de fide. The elements are auto "a play," in law, "an order, decree, sentence," from Latin actus (see act (v.)), de "from, of" (see de), fides "faith" (from PIE root *bheidh- "to trust, confide, persuade"). The Spanish form is auto-de-fe, but the Portuguese form took hold in English, perhaps through popular accounts of the executions following the earthquake of 1755.