Making smart window choices starts with understanding these essential terms:
Awning -- A window with a single sash hinged at the top to open up and out from the bottom.
Casement -- A window with a single sash hinged on the left or right that opens out with a crank or lever. Casements provide maximum ventilation.
Double-hung -- A window with two sashes that bypass each other vertically when opened from the bottom and top.
Fixed glass -- A window that does not open. They come in a variety of shapes to combine with other windows. Large fixed windows are often called picture windows.
"simulated" or "true" muntins.
Gliding -- A window with two sashes that move horizontally in a common frame.
Picture window -- see Fixed glass.
Simulated divided light -- Any window with muntins affixed to the inside and outside of a panel of glass to simulate the look of true divided lights. Snap-on grilles can be removed easily to clean the glass.
Single-hung -- A window that features an upper and lower sash, but only the lower sash is operative.
Sliding -- See Gliding.
Specialty -- This term refers mostly to unusual shapes, such as triangular, round, half-round, and other nonstandard configurations, including bow and bay windows. Most are fixed-sash (inoperative) and are included to create architectural interest.
Tilt -- A double-hung window with sashes that tilt for cleaning.
True divided light -- Any window with multiple individual planes of glass assembled in the sash using muntins.