to diminish gradually and stop; dwindle to nothing, to tire; to exhaust
The earliest known use of “peter” to mean “dwindle” relates to the mining industry in the USA in the mid 19th century, and it’s reasonable to suppose that’s where it originated. The earliest use of the word in that context appears in a piece from the Wisconsin newspaper the Milwaukee Daily Gazette, December 1845.
Another example is this comment in an article on hard-rock mining in Appleton’s Journal of New York, dated 18 October 1873: “No mortal forecast can tell whether a good vein will not narrow to nothing (‘peter out,’ as the miners phrase it) in a week; and, on the other hand, it may widen in that time beyond all anticipation.”
This mining slang describes a promising vein of ore (gold, silver, etc.) that did not live up to the miners’ hopes (“He discovered the lodes had only a poor sickly trace of ore, which soon ‘petered out,’” 1877) By the early 20th century, “peter out” was being used to describe nearly anything that, after a promising start, either failed to “pan out” (another 19th century mining term, from panning for gold nuggets in streams) or simply faded away.
Given the original mining context, a possible explanations for the “peter” in “peter out” is “saltpeter” in the US, known in Britain as “saltpetre,” also known as potassium nitrate, a component of gunpowder. Blasting was a common practice in 19th century mining, and “peter” has been a slang verb since that time meaning “to use explosives.” (“The Dolman boys are going to peter a pawnshop safe tonight.” 1962) So it may be that exploring a promising vein of ore with dynamite and then finding that it leads nowhere gave us “peter out.”
While the root source of ‘peter out’ is fairly certainly mining, there’s no clear understanding of why the word ‘peter’ was chosen in this context. I mean, why not “ralph out” or “bernard out?”
But there is an association between Peter and rock. In Greek, “petros” means rock. “Peter” was also used in the eighteenth century for a kind of loaded dice. And it turns up about the start of the nineteenth century as a slang verb meaning to stop or cease.
At this point, however, the evidence peters out, so nobody really knows.
And the year 2016 is rapidly petering out now. Only a few hours are left.
So, Happy New Year to us all!