PACIARINA — Semiliquid, fine-grained residue derived from polishing seminato floors.
Pâte-sur-pâte — French term for 'paste-on-paste'. A delicate form of low-relief decoration built up by adding layer on layer of white slip on a contrasting ground.
Pendentive — In architecture the triangular portion of a sphere which, in a square or polygonal room, effects the transition from the angles of the walls to a circular dome.
PIZZA / PANCAKE — Circular disc of various thicknesses and dimensions made by pressing molten glass paste.
PLASTER COAT — A mixture of sand, lime putty and cement for protecting walls.
Plastic clay — Ordinary wet clay.
PLUMB — Any vertical surface that is at a perfect right angle to the horizon.
PLYWOOD — A wood formed out of thin layers of veneers laid at right angles to each other. As a general rule, plywood is not a suitable base for tiling.
POLISHING — Polishing is carried out with boiled linseed oil and wax, with a lead polisher or special grindstones and oxalic acid.
Porcelain — A vitreous (glassy) ceramic material characterized by a dense, fine grained and smooth body.
POZZOLANA — Sedimentary, pyroclastic loose rock made of very reactive aluminates and silicates. Pozzolana powder mixed with lime also sets in water. It was widely used by the Romans to prepare mortars.
PRESSED TILES — Pressed tiles are obtained from a mixture of powders, which are compacted and shaped at high pressure in a press, see EXTRUDED TILES.
PRICKING OUT — A method for transferring a design onto a rendered wall or cement base, where the paper design is laid over the surface, and the design is pricked through the paper using a thin, pointed tool.
