registration number

Từ điển Oxford Advanced Learner 8th

regiˈstration number [registration number] BrE NAmE (also regis·tra·tion) (both BrE) (NAmE ˈlicense (plate) number) noun
the series of letters and numbers that are shown on a ↑number plate at the front and back of a vehicle to identify it
See also: ↑license number ▪ ↑registration