gilet
Vest

A vest is a garment worn on the upper body that covers the back, shoulders and chest.

It opens at the front and fastens with regular buttons, snap buttons or a zipper. It is generally worn over something: (shirt, blouse, turtleneck, t-shirt, etc.).
It also refers to a knitted jacket with long sleeves, open at the front.

In some regions of France and in Quebec, the term “gilet” can also refer to any kind of sweater. There is also the cardigan; a “gilet cardigan” or “jaquette” is a jacket buttoned at the front.
It can keep you warm when the weather is slightly cool. It also allows you to adopt a different style.