jam jar(redirected from a jam jar)
slang A car. The phrase comes from rhyming slang in which "jam jar" rhymes with "car." Primarily heard in UK. That's a beauty of a jam jar you've got there. What is it, a '67? My jam jar won't start today—can I get a ride with you?
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.