Coif -

In a military context, the coif is a vital piece of defensive armor designed to protect the head, neck, and shoulders.

: From the 12th to the 15th centuries, it was standard everyday wear for all classes. It was considered "underwear" for the head; no respectable person would appear in public without their head covered, often wearing a more formal hat over the coif . In a military context, the coif is a

In the technical domain of mathematics and signal processing, "Coif" refers to , a specific family of wavelets. Chainmail Coif : 8 Steps (with Pictures) - Instructables In a military context