Where I come it's pronounced 'th'. The connection to numeral order is obvious, but I don't know which one came from which.

  • In CPP, '#' is the prefix for preprocessor (as if there were the other sort) commands.
  • In CPP as GNU extension, inside macros '##' works as an escape that evaluted into a null, with an addition: if used before a "rest" parameter that is empty, it will remove the preceding commas.

    #define foo(a,b...) bar(a,##b)
    foo(a,b)
    foo(a)

    evaluates into

    bar(a,b)
    bar(a)

  • Wall character in ADOM.
  • Prefix for extended commands in NetHack.
  • Comment tag in most text-type configuration files too.
  • One of the classic text separators.
  • Also known as pound and risuaita.
  • Mostly really useless character, which is why it's so damned hard to think of more entries for this list