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

• Lexulous
• Wordscraper
• Wordosaur

ad. In a sempiternal manner; eternally.

ad. in an everlasting manner, as to have an infinite temporal duration; as opposed to eternally or timelessly, as to exist outside time

"Nevertheless it may be said that the sempiternal is not bounded by time (in a weaker sense than Plato ascribes to the Forms) in that what exists sempiternally cannot age."