Definition of regnal in English:

regnal

adjective

  • [attributive] Of a reign or monarch.

    ‘she organizes her material by regnal periods’
    • ‘A new challenge arose when Bessus, who had withdrawn to his satrapy, proclaimed himself King of Kings under the regnal name Artaxerxes V.’
    • ‘An odd handful, notably Buckingham Palace and the Vatican, survive in regnal use; the rest exist purely as public museums.’
    • ‘In England, the official emphasis on regnal and legal continuity played an important part in the process by which the Normans came to perceive themselves as inheritors of the historical traditions of an ancient kingdom.’
    • ‘According to tradition, Numa was the great civil and sacred lawgiver of regnal Rome.’

Origin

Early 17th century: from Anglo-Latin regnalis, from Latin regnum kingdom.

Pronunciation:

regnal

/ˈrɛɡn(ə)l/