Definition of regnal in US English:

regnal

adjective

  • attributive Of a reign or monarch.

    • ‘According to tradition, Numa was the great civil and sacred lawgiver of regnal Rome.’
    • ‘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.’
    • ‘A new challenge arose when Bessus, who had withdrawn to his satrapy, proclaimed himself King of Kings under the regnal name Artaxerxes V.’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.’

Origin

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

Pronunciation

regnal

/ˈrɛɡnəl//ˈreɡnəl/