Secret of the Ages

What is age or ages as it appears in Holy Scripture?

As I understand it, an “age” is usually a “long but limited undisclosed period of time”.

And

“ages” is a sequence of time periods as such (I.e. consecutive ages).

Example verses:

“and to cause all to see what is the fellowship of the secret that hath been hid from the ages in God, who the all things did create by Jesus Christ,” (Ephesians 3:9, YLT)

“that He might show, in the ages that are coming, the exceeding riches of His grace in kindness toward us in Christ Jesus,” (Ephesians 2:7, YLT)

“by faith we understand the ages to have been prepared by a saying of God, in regard to the things seen not having come out of things appearing;” (Hebrews 11:3, YLT)