Quarter glass

Quarter glass (or quarter light) on automobiles and closed carriages may be a side window in the front door or located on each side of the car just forward of the rear-facing rear window of the vehicle. Only some cars have them. In some cases, the fixed quarter glass may set in the corner or "C-pillar" of the vehicle. Quarter glass is also sometimes called a valence window.(AKA quarter lite)

This window may be set on hinges and is then also known as a vent window, wing window, wing vent window, or a fly window. Most often found on older vehicles on the front doors, it is a small roughly triangular glass in front of and separate from the main window that rotates inward (see top right image) for ventilation.