I came across an interesting fact:
Latin saecularis is given as a synonym of Greek aiônios
http://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0057%3Aentry%3Dai)w%2Fnios (http://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0057%3Aentry%3Dai)w%2Fnios)
saecularis is the adjective of saeculum (age)
in the Latin vulgate, Jerome translated aiônios in one sentence both with aeternum and saecularis:
Titus 1:2 (Textus Receptus)
επ ελπιδι ζωης αιωνιου ην επηγγειλατο ο αψευδης θεος προ χρονων αιωνιων
in spem vitae aeternae quam promisit qui non mentitur Deus ante tempora saecularia
this is the definition of saecularis, obviously synonymous with aiônios
http://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0059%3Aentry%3Dsaecu%5Ela_ris (http://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0059%3Aentry%3Dsaecu%5Ela_ris)
maybe interesting for somebody
Yes, we know it as the English word, secular.
sec·u·lar (sky-lr)
adj.
1. Worldly rather than spiritual.
2. Not specifically relating to religion or to a religious body: secular music.
3. Relating to or advocating secularism.
4. Not bound by monastic restrictions, especially not belonging to a religious order. Used of the clergy.
5. Occurring or observed once in an age or century.
6. Lasting from century to century.
n.
1. A member of the secular clergy.
2. A layperson.
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[Middle English, from Old French seculer, from Late Latin saeculris, from Latin, of an age, from saeculum, generation, age.]
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secu·lar·ly adv.
the second meaning worldly was maybe the reason why Jerome translated aiônios with aeternum, not with saecularis, if think that would have changed church history a lot