What does the idiom in a age mean?

The idiom "in an age" is not a common idiom in English. It's likely that you're thinking of "in this age" or "in that age."

Let's break down the meaning of these phrases:

* In this age: This phrase refers to the current time period or era. It signifies the present context and often emphasizes the challenges, advancements, or characteristics associated with the current times.

* In that age: This phrase refers to a specific past period or era. It signifies a past context and emphasizes the characteristics, events, or norms associated with that time.

Examples:

* In this age of technology, it's easier than ever to stay connected.

* In that age of exploration, the world was a vast and unknown place.

Let me know if you meant a different idiom. I'm happy to help you understand its meaning.