Английский Этимологический словарь - pica (1)

- "size of type of about six lines to the inch" (12 point), 1588, probably from M.L. pica, name of a book of rules in Church of England for determining holy days, probably from L. pica "magpie;" the book so called perhaps from the color and the "pied" look of the old type on close-printed pages.