what does crate trained dogs mean?

I booked with a sitter who preferred crate trained dogs in March/2017. My dog ate her shoe and I never understood why. That is so unlike him! I literally just learned that a crate trained dog doesn't mind spending extended periods of time in a crate. I assumed a crate trained dog was simply a housebroken dog. Now I know why he ate her shoe..

This means that a crate was used when potty training. I used a crate to train both of my dogs. It was a sense of safety for them and acted like a den. Most of the time, a dog will not go potty where they sleep. This helps by giving them a small place and as soon as they come out of the crate and go outside that association with going outside will click and with time they are able to have free range of the home with no accidents.