Schedule is a note, it goes back to the Latin word for the strips of plant used to make papyrus sheets; so it's one of the strips and by analogy a written note

Schedule is a note, it goes back to the Latin word for the strips of plant used to make papyrus sheets; so it's one of the strips and by analogy a written note small enough to fit on such a sheet. Schedules are common in UK legislation as addenda to the main clauses/provisions. Most wouldn't fit in a papyrus strip though!