1. Plain plinth or socle of a pedestal, podium, etc.
2. Fillet or list on either side of the scotia in an Attic base, and especially if used with the Ionic Order.
3. Square architectural moulding framing a sculptured relief, panel, plaque, inscription, etc.
"quadra." A Dictionary of Architecture and Landscape Architecture. . Encyclopedia.com. (August 15, 2018). http://www.encyclopedia.com/education/dictionaries-thesauruses-pictures-and-press-releases/quadra
"quadra." A Dictionary of Architecture and Landscape Architecture. . Retrieved August 15, 2018 from Encyclopedia.com: http://www.encyclopedia.com/education/dictionaries-thesauruses-pictures-and-press-releases/quadra