SYM·0086 · Octothorpe
Number sign
a pound of weight, still
- Unicode
- U+0023 number sign · not the sharp U+266F
- Meaning
- Number, when it leads; pounds weight, when it trails; and since 2007, a tag — a word declared to be a topic.
- History
- A ligature of ℔, itself the abbreviation of Latin libra pondo, a pound by weight: the crossed lb collapsed under a fast hand into a lattice. It acquired the name octothorpe at Bell Labs around 1968, when the touch-tone keypad needed a word for the key. Chris Messina proposed using it to group conversations on Twitter on 23 August 2007.
- Variants
- Two horizontals and two verticals, sheared or upright. It is not the musical sharp ♯, whose horizontals slant and whose verticals are upright — a distinct character with a distinct codepoint, routinely substituted for it.
- Related
- @ its partner in second careers; ♯ the character it is constantly confused with; ℔ its own ancestor U+2114.
- Appears
- Telephone keypads, programming languages, American weights, and several billion tagged posts.
- Evolution
- Weight abbreviation → number sign and phone key → the operator that sorts public conversation into subjects.
Sources · 4
- documented The libra pondo derivation, preserved in the surviving character ℔ U+2114 L B BAR SYMBOL.
- documented Chris Messina’s public proposal of the grouping hashtag, 23 August 2007.
- documented The Unicode Standard: U+0023 NUMBER SIGN and U+266F MUSIC SHARP SIGN are different characters.
- traditional That octothorpe was coined at Bell Labs around 1968. The origin at Bell is well attested; the second half of the word is not — the competing explanations, from a tribute to Jim Thorpe to eight fields around a village, are stories told after the fact.