whistle-tip
n.— «A “whistle-tip” is a device that is applied to, or is a modification of, a motor vehicle’s exhaust pipe for the sole purpose of creating a high-pitched or shrieking noise when the motor vehicle is operated.» —“Exhaust Systems: Whistle-Tip Prohibition” California Department of Motor Vehicles Jan. 1, 2004. (source: Double-Tongued Dictionary)
Further reading
Cat hair may be something you brush off, but cat hair is also a slang term that means “money.” In the same way, cat beer isn’t alcoholic — some people use cat beer as a joking term for “milk.” And imagine walking on a...
Have you ever googled your own name and found someone else who goes by the very same moniker? There’s a word for that: googleganger. Plus, the language of hobbyists and enthusiasts: If you’re a beekeeper, perhaps you call yourself a...