regnal number

English

Noun

regnal number (plural regnal numbers)

1. An ordinal number that distinguishes a monarch from others of the same name.
   • 2011, Norman Davies, Vanished Kingdoms, Penguin, published 2012, page 429:

     Umberto I, who had fought at Solferino, had been christened with the name of the dynasty's founder, and changed his regnal number from IV to I.

Usage notes

• Normally written as a Roman number; e.g., Henry VIII for "Henry the eighth".