I was told that the airport abbreviation for O’Hare was “ORD” because the airport was surrounded by “orchards” — I don’t know if any of that is true — or even relevant this article — feel free to call me a threadjacker.
It is located in a small community called Orchard Field, and was a manufacturing site for Douglas aircraft during WWII, hence ORD.
It comes from an airplane factory known as "Orchard Place," that predates the airport being renamed O'Hare. Maybe there were orchards before this factory was built, but you're going back quite a ways.
He says in the article O’Hare was previously called Orchard Field. It was renamned O’Hare shortly after the end of WWII in honor of Chicago native Butch O’Hare, Medal of Honor winner and the Navy’s first ace.