Cantonment is a word that refers to a special area where soldiers stay when they are not fighting. It's like their own little town where they eat, sleep, and do other things they need to do when they're not out protecting our country.
In the cantonment, soldiers have everything they need to stay healthy and ready for their next mission. They have places to eat and sleep, medical care if they get sick, and places to exercise and train so they can stay strong and focused.
Think of it like a really big playground where soldiers go to hang out when they're not at school (or fighting). Just like how you go to school during the day, soldiers go out to fight, but they come back to the cantonment at night to be with their friends and rest up for the next day.