The loose leaf inserted into the register of a monastery on which were recorded notes of daily happenings and events. At the end of the year some of its contents were included in the chronicle being compiled at the monastery. Obviously the scedula was replaced each year. Often enough these notes were made not using a pen but cum plumbo = with lead, which when shaped conveniently could be used as a pencil. From scedula derives schedule.
Dictionary of Medieval Terms and Phrases. Christopher Coredon with Ann Williams.