A "dog pen" is a small enclosed area where dogs are kept, usually outside. It is like a fenced-in play area for dogs to run and play safely. Full definition
Both indoor and outdoor dog pens often offer the option of joining panels together for the purpose of creating larger play areas. (puppy-training-solutions.com)
Make sure that you put a container of fresh water in the indoor dog pen so that your fur baby stays hydrated while they run around, play or sleep in the pen. (itday.com)
There are some pets that can jump higher and so getting a portable dog pen that is 30 inches high would be sufficient and safe. (itday.com)