Common in Cook County, IL (aka Chicagoland), it's when 2 cars, 1 behind the other, come to a full stop at a stop sign and then both proceed through the intersection together even though the law requires the 2nd car to stop again after the 1st car proceeds.
OFFICER: I'm ticketing you for going through the stop sign without stopping.
DRIVER: But I did stop!
OFFICER: No! A Cook County Stop doesn't count. You were supposed to stop again after moving up to the crosswalk