I’m creating this entire post to answer the only question I’ve ever asked that Google couldn’t exactly answer. Not that they exist to exactly answer anything, I understand they’re just a search engine.
I first came across the phrase while reading Thomas Bogg’s peddler application in the archived documents of the East and West Proprietors of New Jersey.

In this scanned image of a handwritten legal document from the 1700’s; Thomas Boggs’ application for a peddler’s permit uses the phrase “Pitty Chapman” as a synonym for “peddler.” But later, it uses an alternate spelling; “petty Chapman” (Capitalization here is as presented).
It was clear that pitty/petty chapman was some kind of a synonym for a street peddler, but how? I have entered it into search a few times and every now and then, Google thinks perhaps I’m interested in pit bull dogs. It’s quite unnerving to confuse a search engine 🙂
Our ancestors might be amused that our modern reliance on standardized spellings tends to blind us to the fact that for most of history, spelling was not an exact thing. Folks would spell their own names differently quite regularly. Folks would use one spelling of their name on legal documents, but spell it different for social or informal circumstances.
Finally I figured out the reason Petty Chapman is a term synonymous with peddler, because a Chapman is a 1500’s word for “merchant.” Petty normally means small and a peddler is a roaming merchant usually of small things.
If you’re tracking the genealogy project or the house project here, just know that even though Slater house was built during the time of the East Jersey Proprietors, so far I’ve found no connection between Thomas Boggs, Slater house, or any of its residents. This post is entirely irrelevant to the rest of my site except that not “Pitty Chapman” is not a maddening search engine black hole.