FLYING BUTTRESS.--A buttress used to steady the upper and inner walls of a vaulted building, placed at some distance from the wall which it supports, and connected with it by an arch. [Illustration: FIG. _U_.--FLYING BUTTRESS.] FOIL.--A leaf-shaped form produced by adding cusps to the curved outline of a window head or piece of tracery. FOLIATION.--The decoration of an opening, or of tracery by means of foils and cusps. FOSSE.--The ditch of a fortress. FRANÇOIS I. STYLE.--The early Renaissance architecture of France during part of the sixteenth century. FRIEZE.--(1) The middle member of a Classic or Renaissance entablature; this was often sculptured and carved; (2) any band of sculptured ornament. GABLE.--The triangular-shaped wall carrying the end of a roof. GABLET.--A small gable (usually ornamental only). GALLERY.--(1) An apartment of great length in proportion to its width; (2) a raised floor or stage in a building. GARGOYLE.--A projecting waterspout, usually carved in stone, more rarely formed of metal. GEOMETRICAL.--The architecture of the earlier part of the decorated period in England. GRILLE.--A grating or ornamental railing of metal. GROIN.--The curved line which is made by the meeting of the surfaces of two vaults or portions of vaults which intersect. GROUP.--An assemblage of shafts or mouldings or other small features intended to produce a combined effect. GROUPING.--Combining architectural features as above. HALL.--(1) The largest room in an ancient English mansion, or a college, &c.; (2) any large and stately apartment. HALF TIMBERED CONSTRUCTION.--A mode of building in which a framework of timbers is displayed and the spaces between them are filled in with plaster or tiles. HAMMER BEAM ROOF.--A roof peculiar to English architecture of the fifteenth century, deriving its name from the use of a hammer beam (a large bracket projecting from the walls) to partly support the rafters. HEAD (of an arch or other opening).--The portion within the curve; whether filled in by masonry or left open, sometimes called a tympanum. HIP.--The external angle formed by the meeting of two sloping sides of a roof where there is no gable. HÔTEL (French).--A town mansion. IMPOST.--A moulding or other line marking the top of the jambs of an arched opening, and the starting point, or apparent starting point, of the arch. INLAY.--A mode of decoration in which coloured materials are laid into sinkings of ornamental shape, cut into the surface to be decorated. INTERSECTION (OR CROSSING).--The point in a church where the transepts cross the nave. INTERSECTING VAULTS.--Vaults of which the surfaces cut one another.