What is 'middle class' anyway? Definitions differ, making it a 'hard question to answer'

photo President Barack Obama speaks Tuesday at Amazon.

President Barack Obama used the phrase “middle class” 17 times during his speech Tuesday in Chattanooga.

But just what does middle class mean?

Is it an income level? A lifestyle? A state of mind?

“It’s really hard to find an exact answer of what the middle class is,” said Amanda Carmichael, executive director of the Ochs Center for Metropolitan Studies. “It is a really hard question to answer.”

Numbers aren’t hard to find — the tricky part is interpreting them.

If you list every Hamilton County household’s income and pick the number smack dab in the middle, that’s the median — or middle — income.