saeculo

Saeculo is the dative or ablative singular form of the Latin neuter noun saeculum, a term that denotes a defined period in time—an age, era, century, or lifetime. In classical and later Latin, saeculum can refer to a span of years, a generation, or the course of history, depending on context.

The noun saeculum itself conveys the notion of a bounded or recognizable period. Its use extends into Christian and philosophical discourse to describe the present age or the whole lifetime of humanity. The word is the source of several modern terms, notably the adjective saecular and its derivatives, which entered Latin later as secularis and then into vernacular and scholarly vocabularies as secular.

In Latin texts, saeculum appears in phrases that locate action in time, such as in hoc saeculo (“in this age”) or saeculo isto (“in that age”). A famous formula, saecula saeculorum, expresses “ages of ages” and occurs in liturgical contexts. The form saeculo is specifically the dative or ablative singular; the neuter noun declines as saeculum in the singular and saecula in the plural (with saeculi and saeculis in the genitive and plural cases, respectively).

Declension note: saeculum is a neuter noun of the second declension. Singular forms include nom/acc saeculum, gen saeculi, dat/abl saeculo; plural nom/acc saecula, gen saeculorum, dat/abl saeculis.

See also: secular, secularism, century, era.