Polygonal: a figure composed of more than four angles, of equal size.
Porte-cochère (pr. port´-co-share´): a covered entrance, under which a carriage can be driven.
Portico: an open space or ambulatory covered by a roof, supported on columns, forming a porch. In Classic temples the front of the portico consists of Columns, Entablature, and Pediment, covered by the extension of the roof of the Cella. According as the Portico has four, six, eight or ten columns in front the temple is distinguished as Tetrastyle, Hexastyle, Octostyle or Decastyle. When the Portico is enclosed on the left and right by an extension of the sides of the Cella it is distinguished as “In Antis.”
Post: an upright supporting member, as of a door. An element in the principle of construction known as Post and Beam.
Post and Beam: generic term for the constructive principle of a horizontal member, supported upon vertical ones.
Posticum (Latin for Epinaos): See Naos.
Pot Metal: glass fused in a crucible.
Pozzolana: a clean, sandy earth, of volcanic origin, used by the Romans in combination with lime to form concrete.
Profile: specifically, the outer edge of the section of a moulding.
Projection: a general term for any member that extends beyond the main planes of a structure, especially used of mouldings.