mid-12c., "a wondrous work of God," from Old French miracle (11c.) "miracle, story of a miracle, miracle play," from Latin miraculum "object of wonder" (in Church Latin, "marvelous event caused by God"), from mirari "to wonder at, marvel, be astonished," figuratively "to regard, esteem," from mirus "wonderful, astonishing, amazing," earlier *smeiros, from PIE *smei- "to smile, laugh" (source also of Sanskrit smerah "smiling," Greek meidan "to smile," Old Church Slavonic smejo "to laugh;" see smile (v.)).
From mid-13c. as "extraordinary or remarkable feat," without regard to deity. Replaced Old English wundortacen, wundorweorc. The Greek words rendered as miracle in the English bibles were semeion "sign," teras "wonder," and dynamis "power," in Vulgate translated respectively as signum, prodigium, and virtus. The Latin word is the source of Spanish milagro, Italian miracolo.