yardstick

noun, a measuring rod a yard long, usually divided into inches (COD) [‘yard’: a unit of linear measure equal to 3 feet (0.9144 metre) (COD)]

“When Jones was building the house he give a contract to a mason … When he got done a foundation and wanted to get paid for it, Jones come out with the yardstick and laid her on top of the wall. He said, ‘This is only thirty inches. It’s supposed to be thirty-six’!”