The podictionary word for today is chaperone:  The average age of a first marriage in the western world is getting darn close to 30 years old.  This means people have pushed the date for wedding bells off almost a decade in only two or three generations.  Our whole structure of finding mates and settling down has changed radically after centuries. 

When my parents got married it was a time when all of the adults in their lives considered it their duty to watch over and guide young people.  Can you imagine a school teacher today having anything to say about the dating habits of their students.  People traveled in smaller circles in those days and a chaperone seems almost quaint now, but back then they were a necessary part of guiding the behavior of generations entering their first phases of sexual awareness. 

So what then does the word chaperone have to do with hats?  In French a chapeau is a hat.  We get our English word cap from the same Latin source cappa. And in fact the word cape is from there too. These words are old enough and pervasive enough that they appeared in Old English before the Norman invasion of 1066 brought all those French roots into Middle English. 

What all these articles of clothing have in common is the fact that they protect the wearer from the weather and it is the protection of young women from inappropriate male suitors that is the job of a chaperone. 

More than 600 years ago when chaperone first appeared as a word in English it in fact did mean a hat or hood.  It was the metaphor of the protective clothing that got the word applied to a person undertaking a protective role.