Was I living in a parallel universe? When I was a kid in 60s England everyone knew the # symbol stood for 'Number'. It was also on British manual typewriters as 'the number key' but I thought it was an Americanism as I was a collector of comics and new Marvel/DC comics were always marketed as "edition #1 out now!". With the coming of push-button phones in the 60s/70s, the # made an appearance on home phones and was still known as the 'number key' but nobody knew what it was for. The term "Hash" seemed to me to come in with home computers in the late 70s/early 80s - I seem to remember references to 'hash' and sometimes 'hatch' when typing in Basic games from magazines for my Sinclair Spectrum