What exactly does it mean when a fire is __ percent contained?

There have been a lot of news stories about fires recently.

That includes wildfires in Canada that caused some smoggy, smoky conditions last weekend, to the more recent Skibo blaze in Minnesota's St. Louis County.

Officials say the Skibo fire is currently 57 percent contained – a significant improvement from yesterday's 21 percent.

But what does it mean when a fire is __-percent contained?

It has little to do with how much of the fire has been extinguished, Public Information Officer Ali Bickford with the Superior National Forest told BringMeTheNews.

Here's how Bickford explained it:

When there's a fire, crews set up a perimeter, making a semi-imaginary line as to where the fire is and where it is not.

Part of that perimeter is considered "contained" when crews do not expect the fire to spread past that part of the line.

So when a fire is 57 percent contained (as it is in Skibo), that means fire is expected to stay within 57 percent of that perimeter or line. However, fire could continue to expand past the other 43 percent of that line that has not been contained yet.