Q&A #13131

Algebra and the # symbol

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From: Pat Ballew (for Teacher2Teacher Service)
Date: Feb 23, 2004 at 15:04:36
Subject: Re: Algebra and the # symbol

  Jeanne already answered your question about the meaning of a#b, but you
asked, "what the name of the symbol #?"  and neatly stepped into my area of
interest... why we call things what we do...

This one is pretty interesting, and I have a little about it at my web page
at http://www.pballew.net/etyindex.html   that you can look at for future
reference, but for now, here is the section on #, which is, by the way,
technically called the Octothorpe...

In the 1960's when Bell Telephone added two new buttons for push button
telephones, they used the * symbol and the # symbol. Although most people
call the * an asterisk, the telephone folks decided to use "star". The other
symbol, #, has been called lots of different names such as crosshatch, tic-
tac-toe, the pound sign, and the number sign (leave it to the telephone
company to put the number sign on one of the two keys without a number); but
the term now used by the American telephone industry for the symbol is
octothorpe although it is more often called the pound key in conversations
with the public. It seems that the name was made up more or less
spontaneously by Bell Engineer Don MacPherson while meeting with their first
potential customer. The octo part was chosen because of the eight points at
the ends of the line segments, and the thorpe was in honor of Jim Thorpe,
the great Native American athelete. Why honor Thorpe? At the time MacPherson
was working with a group that was trying to restore Thorpe's olympic medals,
which had been taken from him when it was found he had played semi-
professional baseball prior to his track victories in the Olympics in
Sweden. [It's not math, but I love the story that when the King of Sweden
gave him the gold medal, the king said, "You are surely the greatest
athelete on the earth". The modest Thorpe smiled and replied, "Thanks,

There are a host of other names for the # symbol, and many of them can be
found at this page from Wikipedia which includes several different stories
about the creation of "octothorpe" or "octothorn" and also has this rather
interesting clip:
"The pronunciation of # as 'pound' is common in the US but a bad idea. The
British Commonwealth has its own, rather more apposite, use of 'pound' sign.
On British keyboards the UK pound currency symbol often replaces #, with #
being elsewhere on the keyboard. The US usage derives from an old-fashioned
commercial practice of using a # suffix to tag pound weights on bills of
lading. The character is usually pronounced 'hash' outside the US. There are
more culture wars over the correct pronunciation of this character than any
other, which has led to the ha ha only serious suggestion that it be
pronounced 'shibboleth' (see Judges 12:6 in an Old Testament or Tanakh)."
The page also disputes the use of "square" in Britain.

 -Pat Ballew, for the T2T service

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