This word is acceptable for play in the US & UK dictionaries that are being used in the following games:

• Lexulous
• Wordscraper
• Wordosaur

n. irregular plural of interregnum

"From this time, whether it was from the favour of the gods being obtained, or that the more unhealthy season of the year was now passed, the bodies of the people having shaken off disease, gradually began to be more healthy, and their attention being now directed to public concerns, when several interregna had expired, Publius Valerius"