from The American Heritage® Dictionary of the English Language, 4th Edition
- n. Slang A van used by police for taking suspects into custody.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A police van for transporting prisoners.
from the GNU version of the Collaborative International Dictionary of English
- n. An enclosed truck used by police to transport prisoners.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. van used by police to transport prisoners
Perhaps from paddy, policeman, from Paddy.(American Heritage® Dictionary of the English Language, Fourth Edition)
Supposedly from the term Paddy (a nickname for an Irishman). (Wiktionary)