Peter out means to dwindle gradually and then stop altogether. The verb belongs to American mining of the 1840s, where a seam that stopped paying was said to peter; the full phrase ‘peter out’ is first recorded in 1854. Why the word ‘peter’ was chosen has never been settled.
What’s the origin of the phrase ‘Peter out’?
The earliest known use of peter as a verb meaning dwindle relates to the mining industry in the USA in the mid 19th century, and it is reasonable to accept that that is where it originated. Thoughts of US mining at that date bring to mind images of the California Gold Rush, which is sometimes suggested as the source of this phrase. The earliest uses of the word in that context come from later, for example, this piece from the Wisconsin newspaper the Milwaukee Daily Gazette, December 1845, which pre-dates the California rush (although there was an earlier Georgia Gold Rush in 1829). The story concerns an old prospector who is comparing his dwindling life circumstances with his diminishing finds of the mineral galena (lead sulphide):
“When my mineral petered why they all Petered me. Now it is dig, dig, dig, drill, drill for nothing. My luck is clean gone - tapered down to nothing.”
Green’s Dictionary of Slang carries that same sentence and dates it to the Quincy (Illinois) Whig of 6 January 1846, a few weeks after the date given here for the Milwaukee printing, so the two records point to one story rather than two.
There are several other records of the use of ‘petering’ to refer to dwindling mining reserves in 1840s USA, although none of these explicitly uses the phrase ‘peter out’. For such a reference we have to wait for a figurative usage in the American lawyer and writer Henry Hiram Riley’s collection of articles - Puddleford and its People, 1854:
“He hoped this ‘spectable meeting warn’t going to Peter-out.”
That is still the earliest citation Green’s Dictionary of Slang gives for ‘peter out’. In Riley’s book the line belongs to a character called Sile Bates, who gets to his feet with it after a request for a collection has been met by a dead calm; the 1854 printing sets it as “war n’t” and “Peter- out”.
By the 1870s the phrase was fixed mining vocabulary. James F. Rusling’s The Great West and Pacific Coast, 1877, lists it in a glossary of western talk, explaining that a “pay-streak” is a vein of gold or silver quartz that will pay to work, and that miners describe one that has stopped paying as having petered out.
An older verb complicates the picture. Etymonline dates a colloquial peter, “to diminish gradually and then cease”, to 1812 and calls its origin uncertain; it gives 1846 for ‘peter out’ as miners’ slang, which is the year of the Quincy Whig story above, while the earliest example of the two words together that Green’s or this page has found is Riley’s of 1854. Green’s Dictionary of Slang takes a bare verb peter, “to stop, to cease”, back further still, to the thieves’ cant of John Poulter’s Discoveries of 1753, where the form is petter and the gloss is “hold your Tongue, let it alone, or stand still”. Green’s leaves the relationship between that verb and ‘peter out’ unresolved, noting only that the plain verb appears to be the earlier.
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. As always, when an etymology is uncertain, people like to guess.
‘Peter’ has many meanings, both as a noun and a verb, and so the speculations are wide-ranging. They include a suggestion of a link to Saint Peter and to the story that his faith in Jesus faded when he denied him before his crucifixion. There could also be a link between St. Peter being called the rock, in Matthew 16:18:
And I say also unto thee, That thou art Peter, and upon this rock I will build my church; and the gates of hell shall not prevail against it.
That may have made an association between Peter and rock, so that a dwindling seam of rock or mineral could be said to have petered out.
Another suggestion is an allusion to the French word péter (to break wind - literally to explode, but also used figuratively to mean fizzle), as in the phrase péter dans la main, meaning ‘to come to nothing’. It is the same French verb that gave English the petard, the small bomb behind ‘hoist with your own petard’.
Of all of the proposed derivations of the word ‘peter’ in the idiom ‘peter out’, the one that best stands up to scrutiny is the link to _saltpetr_e (potassium nitrate). This mineral was a constituent of the gunpowder that was used as an explosive in mining and was also used to make fuses. Saltpetre is at least associated with something that miners would have known something about, that is, mining, as opposed to theology or French quotations.
Green’s Dictionary of Slang narrows the field the same way, quoting Michael Quinion of World Wide Words, who offers saltpetre first and the French peter second and is guarded about both. That is where the evidence stops. The mining setting and the date are secure; the word itself is not, since neither Etymonline nor Green’s commits to a derivation.
See other phrases that were coined in the USA.