To Peter Out

This idiom is used to describe becoming exhausted, giving out, or giving up. Charles Funk in “A Hog on Ice” writes that Lincoln used the expression as a young man, and that the term appears to have originated in America. Mr. Funk speculates that it refers to the Biblical description of the apostle Peter reacting to the seizing of Jesus by grabbing a sword and rushing off to his defense. Within a few hours his enthusiasm has diminished to the point that he denied he even knew Jesus three times. However, the Phrase Finder writes that the term comes from American miners who in the mid 19th century would use it to describe dwindling yield for their efforts. The French word “peter” means to break wind, explode, or fizzle. Saltpeter is a name used for potassium nitrate, a component of gunpowder and fuses. The author speculates that last connection is the most logical explanation for how the expression found its way into the language of miners.