registration

Concise Oxford English Dictionary © 2008 Oxford University Press:
registration/reʤɪˈstreɪʃn/

▶noun

• 1 the action or process of registering or of being registered.

• 2 (also registration mark or registration number) Brit. the series of letters and figures identifying a motor vehicle, displayed on a number plate.

• 3 the action or process of acquiring full British citizenship by a Commonwealth resident or a person of British descent.