[amannm]

Also on the edge of my seat here, wondering what field it could be from. My ChatGPT-esque BS story is that this symbol was misplaced alongside more abstract math-y symbols and was actually briefly used in schematics to identify "lightning conductor" components shown here https://electrical-engineering-portal.com/wp-content/uploads... ... plausible, yes?

[contingencies]

Best theory yet.

[nocoiner]

It’s a good theory, but shouldn’t it show up regularly in electrical schematics then? It doesn’t sound like anyone in any particular fields (other than possibly German mathematics or Dutch economics) has been able to point to historical common usage.