Concise Bible Dictionary:
A period of time marked off by that which distinguishes it from other periods, as the Patriarchal age, the Apostolic age. Though these terms do not occur in scripture, many allusions are made to the different ages. Thus we speak of the Antediluvian age, and scripture speaks of the same period as the “old world,” for example, the ordered scene which God did not spare (2 Peter 2:5). The “Patriarchal age” embraces the time from the call of Abraham to the release from Egypt and the giving of the law. “From Adam to Moses” excluding both, is an epoch when men’s sins could not be classed as transgressions, seeing there was no definite law such as was given to Adam, or such as was administered by Moses (Rom. 5:13-14). Again, from Moses to Christ formed a definite period: “the law was given by Moses, but grace and truth came by Jesus Christ” (John 1:17); “the law and the prophets were until John: since that time the kingdom of God is preached, and every man presseth into it” (Luke 16:16). The time when Christ was on earth is in John’s first epistle repeatedly called “the beginning”: the beginning of Christianity, though it is not called an age. We may also distinguish the period of the Church (from the day of Pentecost until the Rapture of the saints), though it is separated from recognized times and seasons. Our Lord not only spoke of the age in which He was on earth, but referred some events to the end or “completion of the age” (Matt. 13:39-40, 49). The disciples also asked what would be the sign of that completion (Matt. 24:3). Our Lord also spoke of the “coming age,” when His own should receive life eternal (Luke 18:30; compare also Matt. 12:32; Eph. 1:21; Eph. 2:7). God’s kingdom is a “kingdom of all ages” (Psa. 145:13, margin). Eternity, in reference to the glory of God, to the blessing of the saved, and to the punishment of the wicked, is again and again called the “age of ages,” often translated “forever and ever”: all being consummated in the eternal state. The Greek word is αίών throughout, though often translated “world” in the AV (KJV).
Strong’s Dictionary of Hebrew Words: