In an everlasting manner, as to have an infinite temporal duration; as opposed to eternally or timelessly, as to exist outside time(adverb)
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Use "sempiternally" in a sentence
"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."
"My staff of love, sempiternally in a good case, will, satyr-like, be never toiled out — a thing which all men wish for, and send up their prayers to that purpose, but such a thing as nevertheless is granted but to"
"And if gratitude and thanksgiving be to be estimated and prized by the affection of the benefactor, that is to be done infinitely and sempiternally; for the love which you bear me of your own accord and free grace, without any merit of mine, goeth far beyond the reach of any price or value."