Along the lines of what stebu and jenbel were saying....

Let me put it this way. Over the past 25 years my taste in steaks hasn't changed, but what I order has. "Back in the day" I liked mine medium rare....so nowadays I order medium and get the same thing!

But rather than trust someone else's "definition", the best thing to do, as others have said, is to specify the designation, then explain exactly what it is that you want. In my case that would be "pinkish, hot center".