Eternal

Eternal is an adjective describing something that has no beginning or end or exists outside time. In common usage it connotes timelessness or lasting forever beyond human comprehension.

Etymology: from Latin aeternus "perpetual, timeless," from aevum "age, life span." The term is used across languages with cognates such as French eternel, Spanish eterno, and Greek aionios in philosophical or religious contexts.

In religion and theology, eternal life or the eternal soul describe existence beyond death. In philosophy, "eternal" is used in terms such as eternalism, the view that all points in time—past, present, and future—are equally real, in contrast to presentism. In everyday language, "eternal" can emphasize vast duration as a metaphor, as in an "eternal wait" or "an eternal optimist," though such uses are figurative.

Distinctions: "eternal" often implies no beginning or end or timelessness; "everlasting" usually stresses endurance from a beginning to an end that never occurs; "ageless" emphasizes appearance rather than duration. The nuance is subtle and context dependent.