saeculum, saeculi (n)
age / world / century Numbers & Time
2nd declension neuter. In saecula saeculorum (Forever and ever — lit. unto ages of ages)
In Scripture
Increpasti gentes, et periit impius : nomen eorum delesti in æternum, et in sæculum sæculi.
Thou hast rebuked the Gentiles, and the wicked one hath perished; thou hast blotted out their name for ever and ever.
Psalmi 9 · 6