86 that slang etymology

Sometimes the universe hints strongly at what I should write about. Recently I read two books in close succession that featured the same curious slang word, used in different ways and worth a quick study. For one thing, it’s not just a word but a number: 86.

First there was Merritt Tierce’s fierce first novel Love Me Back. Its narrator, who works in a restaurant, says:

Later that day I am in the wine cellar updating the eighty-sixed list when the Bishop’s handler comes by.

Then I read Alison Bechdel’s brilliant comic memoir Fun Home, which shows another usage of 86 and a speculative origin story – but is it true? (Click images to embiggen.)