αἰώνιος (aiōnios)

The adjective aiōnios describes something that lasts for an age or is eternal. Derived from the noun for "age" or "era," it carries a sense of duration that extends beyond the immediate present. In the New Testament, this word appears 67 times, with significant usage in the Gospels of Matthew and John, as well as in First John.

Lexical sources indicate a broad range of meaning. It can describe qualities without beginning or end, such as the eternal nature of God referenced in Romans 16:26. More commonly, it modifies nouns to indicate unending duration, whether positive or negative. This includes "eternal life" in John 3:16 and "eternal fire" in Matthew 18:8, showing that the term applies to both blessing and judgment.

A notable feature of its usage is its connection to the concept of time periods. While often translated simply as "everlasting," the root implies a quality belonging to the coming age rather than just infinite length. This distinction helps explain why translators sometimes use "eternal" for past realities, like God's grace in Titus 1:2, and other times for future states, such as the punishment in Matthew 25:46.