What does Escape Hole mean?

A lot of material design guidelines say "minimum escape hole" width. What does this mean?

An escape hole is usually involved when createing an object with a hollowed out center. When they print the model, it allows un fused material to be removed from the interior, just leaving the printed object behind. A technique that saves on price, since less material is the result.

Keith

If you trap yourself inside your own design, this escape hole can be very helpful for you to get out .... :laughing:

LOL!