The word Abacot is an interesting example of how an error in proof reading invented a word.bycoket2

Apparently the word originated in a misprint of Edward Hall’s Chronicle of 1548 and was then picked up and used by others who thought it was, in fact, a real word.

In 1882, James Murray of the Oxford English Dictionary made the case that the original word was supposed to be bycoket which was taken to originate from an Old French term for a small fort built upon a hill.  The bycoket was in fact a form of headdress which was peaked both in front and behind.

Oddly enough, since other heraldry source books have included the word Abacot as a word for a cap worn by the Kings of England, the student of heraldry may have the occasion to stumble upon the word used in that context by authors who thought they were using an actual word.