Well, it calls itself a pronunciation guide, but it’s about how to refer to punctuation and special characters: ASCII special characters pronunciation guide. It’s at Westminster University in London. Here, for example, are terms referring to #:

bq. crosshatch, pound, pound sign, number, number sign, sharp, octothorpe, hash, (garden) fence, crunch, mesh, hex, flash, grid, pig-pen, tictactoe, scratch (mark), (garden) gate, hak, oof, rake, sink&, corridor&, unequal, punch mark

There was a discussion on FLEFO at CompuServe recently about the origin of the word octothorp(e). Here it is said to come from ‘Bell System’. Here’s a possible etymology: a combination of ‘eight points’ and the surname of Jim Thorpe, an athlete.

The Octothorp Press produces a more fanciful etymology, from Robert Bringhurst:

bq. The word “octothorp” is so obscure that isn’t even in the Oxford English Dictionary (first or second editions). Here’s how the typographic stylist and philosopher Robert Bringhurst defines “octothorp” in his brilliant Elements of Typographic Style (p. 282):

bq. Otherwise known as the numeral sign. It has also been used as a symbol for the pound avoirdupois, but this usage is now archaic. In cartography, it is also a symbol for village: eight fields around a central square, and this is the source of its name. Octothorp means eight fields.