What is Broadsheet?

Legal Definition
A broadsheet is the largest newspaper format and is characterized by long vertical pages (typically 22 inches or 560 millimetres). The term derives from types of popular prints usually just of a single sheet, sold on the streets and containing various types of material, from ballads to political satire. The first broadsheet newspaper was the Dutch Courante uyt Italien, Duytslandt, &c. published in 1618.

Other common newspaper formats include the smaller Berliner and tabloid/compact formats.
-- Wikipedia
Legal Definition
The largest of the various newspaper formats and is characterized by long vertical pages (typically 22 inches / 559 millimetres or more). The term derives from types of popular prints usually just of a single sheet, sold on the streets and containing various types of material, from ballads to political satire.