This was originally the Old English Bryant and defined as the number of books in my ancestor's library (= 4577 books), divided into the Habryant (= 2289 books), the Sitter [or Rhoom] (= 1104 books), the Dinky (= 161 books), the Wallshel (= 23 books), and the Bedside (= 17 books).
But metrication makes fools of us all. The SI unit is the Metric Bryant (=1000 books).
James Bryant
http://www.dendarii.com/bujold_lst.html#bryant