A Dutch cap can refer to two different things:

1. A style of womans hat associated with traditional Dutch costumes. It is usually made of white cotton or lace and can be characterized by triangular flaps or wings that turn up on either side. It can resemble some styles of nurses hat.

2. A contraceptive diaphragm or cap, which is a circular dome made of thin, soft silicone thats inserted into the vagina before sex. It covers the cervix so sperm cannot get into the uterus. When you first start using a diaphragm or cap, a doctor or nurse will examine you and advise on the correct size. It does not provide reliable protection against sexually transmitted infections (STIs) .