The Pound Sign

Date: 04/06/2001 at 23:46:03
From: Mary Yarnold
Subject: the correct symbol for "pound" weight

Dear Dr. Math:

I hope you can answer this question for me. My friend says that you 
can use this sign "#" to mean pound, but I disagree. Her reasoning is 
that it is called the pound button by anyone using a touch-tone phone. 
I have always believed that the symbol lb. is correct for this weight 
abbreviation. What do you think?

Sincerely,
Mary Yarnold

Date: 04/07/2001 at 00:52:17
From: Doctor Douglas
Subject: Re: the correct symbol for "pound" weight

Hi Mary,

The American Heritage dictionary says that you can use it to mean 
weight:

   http://www.bartleby.com/61/84/P0488450.html   

Of course, in American it is usually used to designate "number," as in

     #5   "number five"

When referring to weight, it is usually written after the number:

     4#   "four pounds"

See also this Maricopa College computer science page, which gives 
other names ("octothorpe," "hash") for this symbol:

   http://cs0.math.sc.maricopa.edu/forums/cis162/messages/11.html   

I hope this helps.

- Doctor Douglas, The Math Forum
  http://mathforum.org/dr.math/