The Palladian window consists of three individual windows: a large, arched window in the middle accompanied by two narrower windows on each side. This style of window was popularized by Andrea Palladio, but the style can be traced back to Sebastiano Serlio in his book L’architettura, written in 1537. Sometimes this style of window is referred to as the Venetian window or Serlian motif. This window was used in European and American architecture after the Renaissance. This information is from Britannica and Lindsay Daniel Architecture. The image is from Wikimedia Commons and is Public Domain.