Portcullis.—A strong grating of timber which slid up and down in a groove, to protect the entrance of a castle or fortified house.
Principal (Rafter).—A massive framing of wood which spans a building from wall to wall and carries the purlins.
Purlin.—A stout piece of timber resting on the principals and carrying the common rafters.
Quatrefoil (in Tracery).—A form composed of four segments of circles.
Quoins.—The external angles of a building; also the stones which form the angles.
Respond.—A half-column attached to a wall.
Ribs (Stone).—Narrow projecting stones which form the framework of vaulting.
Sash-Window.—A window in two halves, one over the other, which slide up and down.
Scantling.—The dimensions of a piece of timber in breadth and thickness.
Screens.—The entrance passage formed at the end of a hall by the screen.