A mob cap or mob-cap is a round, gathered, or pleated cloth (usually linen) [[hat]] consisting of a caul to cover the hair, a frilled or ruffled brim, and (often) a [[hat ribbon|ribbon band]] to keep it in place (modern versions use elastic). 

Worn as an indoors hat by married women in the 18th & early 19th century. Depending on the location and era, it was also worn by [[maid]]s as an alternative to the stereotypical maid headdress. During the time period, it was called a [[bonnet]] but is not to be confused with the more general use of the term.  Use this tag in preference to the other when applicable rather than as a sub-type.

Commonly associated with the [[Touhou]] games because of the author's fondness for putting them on many of his more popular, early Windows-era characters.
モブキャップ