Meanings of foolscap sheets in English

All small notes on slips of paper were left, but almost every article written on full-sized foolscap sheets was abstracted.

When he did, it was clutching a rolled series of foolscap sheets, brittle, dusty, and yellowed with age, tied up with a ribbon.

It was a stack of foolscap sheets rising to the thickness of three fingers, creased and compressed from long immurement, but still perfectly legible.

"Sorry!" Cecil would say shortly, and taking up her pencil slash scathing comments at the side of the foolscap sheets.