What it means can be understood in the context of a concrete example.

Here are some concrete examples of what I have in mind.

A concrete example could be in the use of computer databases.

Let me give a concrete example of what I mean.

Since the matter can become intricate, let us take a concrete example.

I asked him to be specific and give me concrete examples.

Some concrete example of what he'd been trying to teach them in his letters.

I would like to pick out a few concrete examples.

We need to have a concrete example of your commitment.

Let me give a concrete example which the Commissioner knows well.