mouse
n.— «Meanwhile, the Stinebakers make no attempt to conceal the fact that the Thunderbird—at least to some devout worshippers of domestic vehicles—is sort of a sacrilegious Frankenstein machine. Inside the Ford body sits a Chevrolet small-block engine. The motor is known to enthusiasts as a “mouse”—big-blocks are known as “rats”—so a small rubber mouse serves as the car’s mascot. The Stinebakers also adorn the dashboard with a sign reading “Built Ford tough with Chevy stuff.”» —“Kicking’ It” by Daniel Pike State Journal-Register (Springfield, Illinois) Sept. 24, 2006. (source: Double-Tongued Dictionary)
Further reading
A listener named Mark now lives in San Diego, California, but grew up in Chicago, Illinois. There, he recalls, when he and his friends played sandlot baseball, cards, or board games, if an opponent tried to get around the rules and then got called...
David from Matthews, North Carolina, grew up using the term cheese toastie for a type of grilled cheese sandwich. Cheese toasties are familiar in Ohio, Indiana, and Illinois, particularly around the cities of Decatur and Springfield. In the UK...