A Venetian blind has horizontal slats, located one above another. Venetian blinds are basic horizontal slats made of metal, vinyl, PVC, or plastic. Wood slats are sometimes used but in the US these are now usually referred to as wood blinds.
They received the name venetian blinds because they maybe originally came from Venice, Italy. These venetian blinds replaced or were used instead of fabric curtains or shutters.
Related patents were taken out by Edward Beran on 11 December 1769, but Venetian blinds were known to the French long before then. In 1761, St. Peter's Church, Philadelphia had such blinds.
In the late 19th and early 20th centuries, Venetian blinds were widely adopted in office buildings to regulate light and air. A large modern complex in the US that adopted Venetian blinds was Rockefeller Center's RCA Building (better known as the Radio City building) in New York City, completed in the 1930s. One of the largest orders for Venetian blinds ever placed was to the Burlington Venetian Blind Co., of Burlington, Vermont, which supplied blinds for the windows of the Empire State Building in New York City.
According to wikipedia