“86” would be, perhaps, an electrical term.
In plants and large substations, the protective relay system is designed to remove short-circuited equipment from service while retaining the remainder of the electric grid. For example, in a substation, if there’s a short circuit on a substation bus (the thick conductors that tie many lines together), the relay scheme is designed to trip breakers to isolate the shorted (faulted) bus and maintain power everywhere else.
Now, in order to trip many circuit breakers, and lock them in the tripped (open) position, an auxiliary relay is often utilized. All relays have a function number, and the lockout relay is designated an “86”. So, if a squirrel gets on a substation bus an creates as short circuit condition, the detecting relay sees the short circuit, and it in turn, causes the “86” relay to operate, causing many circuit breakers to open.
The result - a dead substation bus, no ability to put back in service without human intervention, and all the rest of the grid remains intact. The substation bus is “86’ed” and cannot be resuscitated while the rest of the grid is intact.
An 86 on a human is a hit. Whitless is calling for a hit on the president.
86 - IIRC, is a term that used to be related to Whiskey that was about the strength of beer or a wine spritzer. If a bartender 86’d you he was essentially cutting you off likely cause you had enough.
In the food industry, it means that item is no longer available.
8645 is currently being printed on T shirts-supposedly meaning get rid of Trump. With the usual double speak language, it could be an assassination signal, but the use is pretty common. Bars and restaurants aren’t the only industries to use it, but they are the ones that I am familiar with.