steenth /STEENTH/. adjective. The latest in an indefinitely long series. Derived from “sixteenth” > from Old English siextēne (six and ten) and still used that way in stock trading, where it refers to 1/16 of a point in price. See also: umpteenth.
“There’s this Monaco gook. He snoops around in his yacht, digging up telescope-eyed fish, and people talk about it. ‘Another darned fish,’ they say. ’That’s the ‘steenth bite the Prince of Monaco has had this year.’ It’s like a soap advertisement.” (P. G. Wodehouse)
“The Commissioner almost beats his own head against the desk in his exasperation as he reiterates over and over: ‘But why? Why? Why?’ And for the steenth time, he gets the same indigestible answer: ‘Because he was killing me.’” (Cornell Woolrich)
“A jiffy later, I was on my way up, and another steenth of a jiffy I was at the eaves…” (Paul Hutchens)