Definition of pie wagon in US English:

pie wagon

noun

US
  • 1A vehicle or mobile stand selling pies or other food.

  • 2Slang. A police van; a van used to transport prisoners to jail. Now rare.

Origin

Mid 19th century; earliest use found in The Mountain Democrat. From pie + wagon.

Pronunciation

pie wagon

/ˈpʌɪ waɡ(ə)n/