The traditional-british Series

Further Information

These sizes are no longer commonly used since the UK switched to ISO sizes. Many of these sizes were only used for making books and would never have been offered for ordinary stationery purposes. Foolscap folio is often referred to simply as 'folio' or 'foolscap'. Similarly, 'quarto' is more correctly 'copy draught quarto' and 'Kings' is an alias for 'Foolscap quarto'.

Source: Wikipedia