⍼ The Most Mysterious Unicode Symbol
"I had no idea what it meant or was used for, thus assigned it a “descriptive name” when collating the symbols for the STIX project. (I still have no idea, nor can supply an example of the symbol in use.)"
⍼ is described in Unicode as RIGHT ANGLE WITH DOWNWARDS ZIGZAG ARROW, assigned the value U+237C in the Miscellaneous Technical section, and is given the HTML entity ⍼
I'm not going to bore you with too many details, either about Unicode or the history of it. In short, Unicode is a mechanism to enable any computer software to use one of the currently 144,697 symbols used in a huge variety of human languages and mathematical, scientific and technical applications. It includes hieroglyphs, astrological symbols, various emoji, typographical, and Braille symbols. In short, you can use these glyphs to construct Russian, Chinese, Cherokee…Unified Canadian Aboriginal Syllabics, and the list goes on.
But one of these symbols defies all logic, being a symbol with no apparent use whatsoever. The angzarr seems to exist in a vacuum of unknowability, even prompting one Jonathan Chan¹ to spend years researching its origins. It seems to have originated with the ISO in 1991² before being incorporated into the STIX project, intended to provide a set of standard symbols for maths and engineering. From there it moved into the Unicode standard in 2002. It was, of course, included in LaTeX, MathML and other layout and publishing schemes. But no-one understood exactly where it had come from, what it meant or how it was used. Even the people who developed Unicode didn't, hence Barbara Beeton's quotation above. She even elaborated on this uncertainty:
…it is the case that ISO 9573-13 existed long before either AFII or the STIX project were formed…I once asked Charles Goldfarb what the source of these entities was, but remember that he didn’t have a definitive answer.
Many attempts have been put forward to explain it, from a warning of electrical danger to mathematical graphing and even its origins as the magical Ellis sigil. My favourite is that someone at some point paid to include it (yes, apparently this was a thing!), possibly as a joke. Of course this means that we are now free to assign whatever meaning or value we choose to it. According to Chan, "…the meaning of ⍼ will be whatever meaning is assigned by whoever uses it next… if anyone uses it at all." Perhaps it will turn out to be an Orcish runic symbol referring to Tolkien's Angmar. And who knows, that could be it.
If you want to read the whole sordid tale with lots of technical details, read Jonathan Chan's blog article¹ or for a more accessible trot through the whole sorry mess, there's also a mostly-accurate YouTube video from Half As Interesting. I recommend the latter. And yes, of course there's an xkcd for it. There's an xkcd for everything.