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registration number

British  

noun

  1. a sequence of letters and numbers assigned to a motor vehicle when it is registered, usually indicating the year and place of registration, displayed on numberplates at the front and rear of the vehicle, and by which the vehicle may be identified

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012