What is "Both Side and Two Pages Each Side" or "Multiple Page" or "nUp" printing

This printing option available only on printerplug.com and provide a way for cost effective printing. This option when selected prints 2 pages on front and 2 pages on back of the paper sheet. So total of 4 pages get printed, 2 on front and 2 on back. This is called multiple page printing as well. After printing it looks like above.

If binding is selected, it is then bound left short edge .