Definition: An emphatic and more poetic word for "eternal," "timeless," "temporally infinite."

Usage: Use today's word when you wish to emphasize the long length of a period of time in a way that listeners won't forget. It is also an attractive adornment of any poetic setting. Simply add the traditional –ly to create an adverb.

Suggested Usage: Given the fact that "forever" and "eternal" are longer than most of us can conceive, words like today's are used mostly for hyperbolic effect, "Joshua, you are a sempiternal fountain of youth! What do you take?" However, this hyperbole has an important function—it emphasizes a deep emotional investment in an important long-term relation, "I will be sempiternally grateful to you for telling me so much about myself that I was unaware of."

Etymology: Today's word comes from Late Latin "sempiternalis" from Latin "sempiternus," a compound of semper "always" (as in the Marine Corps motto semper fidelis "always faithful") + aeternus "eternal." Latin "semper" is a truncated form of the phrase for "once and for all," comprising sem- "once" and per "for."