Bonnet is a fairly general term for headgear usually with the forehead uncovered and the back of the head covered without a brim. More regularly used to describe women’s headgear but also used for men too. Bonnets have been around since the Middle Ages right through to the present day. Another feature of the bonnet is that it can be tied under the chin.
Bonnet has also been used in Scotland to describe a steel helmet and also the Scottish Blue Bonnet which is a large floppy beret-like cap.
From the 18th century bonnet forms of headgear, previously mostly only worn by elite women in informal contexts at home, became adopted by high fashion, and until at least the late 19th century, bonnet was the dominant term used for female hats.
In the 21st century the most common bonnets are worn by babies and Scottish soldiers. They are also still worn by women as outer Christian headcoverings in the Amish, Brethren and Mennonite churches among the Anabaptist denominations and some Quakers.
Bonnet derives from the same word in French.