Louver

[1] [2] Louvers originated in the Middle Ages as lantern-like constructions in wood that were fitted on top of roof holes in large kitchens to allow ventilation while keeping out rain and snow.

Later, they evolved into more elaborate designs made of pottery, taking the shape of faces where the smoke and steam from cooking would pour out through the eyes and mouth, or into constructions that were more like modern louvers, with slats that could be opened or closed by pulling on a string.

This includes changes to the window and glazing requirements for homes located in a Bushfire Attack Level category greater than BAL-Low.

Louvers are part of the design of Demerara windows to help keep 18th and 19th century buildings cool in hot climates and block direct sunlight.

They are designed to allow floodwaters to enter and leave the building, equalizing hydrostatic pressure on the walls and mitigating structural damage due to flooding.

They have also been used over the years in hoods, trunk lids, and other various body panels; typically hot rods, but by no means exclusive to that period.