Siglo, Spanish for “century”, closely related to the English secular.
How? The connection seems surprising.
Both come from the Latin saeculum, meaning, “age, span of time, generation”.
The evolution from saeculum to siglo is obvious: a century is just a unit or breakdown of time.
But in English, it evolved into the sense to mean “worldly.” While the religious concerns itself with the spirit and the “other-worldly,” it is the characteristics of time — growing, aging — that are are the most fundamental characteristics of this world.
Life in the real world, in other words, is defined by getting old.