A tracery is an architectural element that divides windows (or screens, panels, and vaults) into pieces of varying dimensions using stone bars or moulding ribs. It is most typically used to describe the masonry pieces that support the glass in a window. The word comes from Latin tracēre meaning "to cut," and refers to the pattern of holes (traces) that are cut into the stone.
Traceries can be used to divide large windows into many small ones without requiring multiple single-pane lights. They also provide decorative contrast between the light-transmitting glass and the background wall or roof. Traceries are often found in church windows but are also seen in windows for other buildings such as museums and libraries.
The word is also used more generally to refer to any intricate design created out of stone. For example, a tracery of flowers might be used as a border around a garden path. In this case, the term "tracery" would not necessarily imply that the hole patterns are used to divide the space inside the border from the outside.
The word "tracery" may also be used to describe the design of trees and their branches. An example would be the tracery of leaves on a beech tree. Here too, the word does not imply that the hole patterns are used to divide the space inside the leaf from the outside.
A sill is the major horizontal portion that forms the bottom of a window frame. The term comes from the Dutch word zij, which means side.
The sill must be strong enough to support the weight of any glass or plastic pane that is placed in it. It should also be thick enough so that it does not bend under the pressure of the lintel or header beam above it.
The sills on most windows are made out of wood. If you look at a window frame, you will usually see several pairs of wooden rails running across the top and bottom of the frame. These are known as stiles. There are many different names for the parts of a window frame, including jamb, sill, headjamb, headstile, and headrail. But whatever name you choose, they all do the same thing: they form the sides of the opening through which you can place things like windows or doors.
Sashes are the vertical portions of a window unit that fit inside the jamb of a window frame. They are usually made out of wood or vinyl. Each sash has two parts: the stile and the rail.
The framework that keeps the glass in place is the moveable portion of the window. A sill is a component that goes at the bottom of a window frame. A stile is the vertical portion of a sash. Top and bottom rails are the horizontal parts of the frame surrounding the pane of glass.
A jamb is the term used for the vertical piece of wood that fits into a window frame. The word comes from the French jambe, meaning leg. Thus, a jamb has two legs.
A header is the name given to the horizontal member on which the sash rides when it slides up or down. The most common type of header is the flat one, which rests on top of casing blocks inside the frame. A transom is the name given to the header on which the sash does not sit but instead covers it. The transom hangs over the side of the frame. It can be flat or raised as in a door transom.
A footer is the name given to the horizontal member below the jamb into which the sash fits when it closes the window. It usually sits on the floor but may also be raised like the header.
A wedge is a thin piece of wood or metal used to keep windows open or closed.