Wiktionary
n. A license plate whose identifier is choose by the registering owner.
Wikipedia
A vanity plate or personalized plate ( US); prestige plate, private number plate, cherished plate or personalised registration ( UK); personalised plate ( Australia, New Zealand and UK) or custom plate ( Australia and New Zealand) is a special type of vehicle registration plate on an automobile or other vehicle. The owner of the vehicle pays extra money to have his own choice of numbers or letters, usually forming a recognizable phrase, slogan, or abbreviation on their plate. Sales of vanity plates are often a significant source of revenue for North American provincial and state licensing agencies. In some jurisdictions, such as the Canadian province of British Columbia, vanity plates have a different color scheme and design.
Usage examples of "vanity plate".
I couldn't read the name on the vanity plate, but I knew I was looking at the trunk of Dow Purcell's silver Mercedes submerged in the depths.
Normally he wouldn't have paid attention to the style of the vehicle, but this one had a vanity plate that said in green capital letters: cojones.
The car was a four-door sedan, a conservative black with a vanity plate that read BULL MKT.
There was only one car out back: a 1972 Buick with a vanity plate that read: FALS TTH.
A snitch of Marino's says he saw a black Jeep with a vanity plate in the area where Susan was shot and about the time we think it happened.
My wife she made me put on that damn, what-you-call-him, vanity plate.