Definition: of little value
This is a historic Spanish coin, but most people probably know it as the name of a New Orlean’s newspaper: The Times-Picayune. It paper was so-named because it originally cost one Picayune.
(Though mostly associated with the French, New Orleans was owned by the Spanish in the late 1700s. It was purchased by the United States in 1803 during the Louisiana Purchase, and became a state in 1816. I presume Spanish currency was still accepted for some time after that.)
Why I Looked It Up
In Uncle Tom’s Cabin, one of the characters says the following about why he doesn’t read the Bible:
“Oh, I didn’t need it,” said St. Clare. “I can learn what does me as much good as that from The Picayune, any time, and smoke a cigar besides; which I can’t do, you know, in a church.”
The character said this in New Orleans in 1851. The Picayune merged with the Times-Democrat in 1914 to become the Times-Picayune.
Added on July 6, 2023
I added the definition above, after finding this in The Tyranny of Clichés:
Refuse to obey even the most picayune law and eventually a man in uniform with a gun on his hip is going to come talk to you.