90% confidence interval

Can anyone please tell what it means when we say:

"These intervals cover the true population median for approximately 9 out of 10 samples taken."

I dont understand the meaning.

I can see how "these intervals", plural, could be misleading- but they are talking about the general concept of "90% confidence levels". One set of samples will have one 90% confidence level and, on average, 9 out or 10 of the medians of those samples will be in that interval. Another way of phrasing it, and, I think, better, is that the probability each median will be in the interval is 0.90.

Thanks heaps...................appreciated