[ gdw]
Some confusion with porte1 (‘door, gate’) and postiz1 (‘postern, wicket, gate’) seems possible, especially in case of the Purg S Pat2 citation. Gdf includes portice solely as a variant spelling of postic (‘poterne et aussi arcade ou portique à front de rue donnant accès à une avant-cour’, 6,336a) which seems unlikely, as the word derives from a different etymon.