Printed matter spread over an entire sheet of paper. The whole must be in one type and one measure, i.e. must not be divided into columns. A folio is when the sheet is folded, in which case a page occupies only half the sheet.
“Pamphlets and broadsides were scattered right and left.” —Fiske: American History, chap. vii. p. 341.
In naval language, a broadside means the whole side of a ship; and to “open a broadside on the enemy” is to discharge all the guns on one side at the same moment.