MRE is an initialism that meals Meal, Ready-to-Eat. There are a multitude of corporations that make MREs, and even the government manufactures them as well. Government-manufactured MREs are mainly made for the military, but there are branches like the FBI and Forest Service that also use them. Field service operations like firefighter crews can make use of MREs. The government also gives MREs to civilians after a natural disaster or attack.
There are a few basic elements of your average MRE. The most important component is the full meal that’s ready to eat right out of the pouch. It’s usually sealed in durable and waterproof packaging, to make sure it won’t get damaged in any kind of disaster.