bonnet Definition

1. A type of hat fastened under the chin with ribbon, formerly worn by women but now worn especially by babies.
(Brit)
2. The hinged cover over a motor vehicle's engine. N Amer equivalent hood.
(Scots)
3. A brimless cap made of soft fabric, worn by men or boys.
4. naut.
An additional part laced on to the foot of a jib¹, etc to gather more wind.
5. A wire cowl over a chimney-top.