The idea sparked my interest so I Googled it... In my growing file on computer subnotebooks, I have this letter on a related subject: "Recently, in speaking to a British friend in London," writes Roni Finkelstein of Colchester, Conn., "I referred to my pocketbook. When it became obvious that he was totally confused as to my meaning, I pointed to it. 'Oh,' he said, 'your handbag.' How and when did the word pocketbook come into common American usage?" That's easy; in 1617, the word first surfaced to denote a small book, now called a notebook; it was a book of addresses, or notes, that fitted in a pocket. By 1816, women were carrying a booklike case with compartments for papers and knickknacks, and they called it a purse, handbag or -- extending the old term -- pocketbook.