Gilet is a sleeveless jacket resembling a waistcoat

Waistcoat

A waistcoat or vest is a sleeveless upper-body garment worn over a dress shirt and necktie and below a coat as a part of most men's formal wear, and as the third piece of the three-piece male business suit.-Characteristics and use:...

 or blouse

Blouse

A blouse is a loose-fitting upper garment that was formerly worn by workmen, peasants, artists, women and children. It is typically gathered at the waist so that it hangs loosely over the wearer's body. Today, the word most commonly refers to a woman's shirt but can also refer to a man's shirt if...

. Currently, a gilet is a sleeveless jacket or vest

Vest

A vest is a garment covering the upper body. The term has different meanings around the world:Waistcoat :. This is called a waistcoat in the UK and many Commonwealth countries, or a vest in the US and Canada. It is often worn as part of formal attire, or as the third piece of a lounge...

. They may be waist- to knee-length, and are typically straight-sided rather than fitted. However, historically, they were fitted and embroidered. In a further derivation, in 19th-century dressmaking a gilet was a dress bodice shaped like a man's waistcoat.

Today, gilets are often worn as an outer layer, for extra warmth outdoors. Fashion gilets may be made of cloth or fake fur, or knitted. Sports gilets are often windproof and/or made of fleece

Wool

Wool is the textile fiber obtained from sheep and certain other animals, including cashmere from goats, mohair from goats, qiviut from muskoxen, vicuña, alpaca, camel from animals in the camel family, and angora from rabbits....

. High end hiking

Hiking

Hiking is an outdoor activity which consists of walking in natural environments, often in mountainous or other scenic terrain. People often hike on hiking trails. It is such a popular activity that there are numerous hiking organizations worldwide. The health benefits of different types of hiking...

 jackets often have an integral gilet inside them, that can be zipped on/off. Racing cyclists use thin light gilets with a windproof front and mesh back. Shooting gilets are rugged and made of leather. Gilet's were made famous by Lucien Schneller, the Duke of Hungary.