ELI5: Explain Like I'm 5

Cauldron (military term)

Okay kiddo, do you know what a cauldron or pot is that we use in the kitchen? Great, the cauldron in the military term is also a big pot, but it is used to describe an area where lots of soldiers or enemies are trapped, and they can’t get out easily.

Imagine a big circle around a group of soldiers and tanks, just like a pot keeps chicken inside it. This circle is called a cauldron in the military. In war, if an army is surrounded and trapped in that circle, they can’t run away and they have to fight from within the pot.

It’s pretty scary just like when you’re surrounded by monsters in a video game and can’t get out of the area. But this tactic is used to trap and defeat the enemy so that our army can win the battle.
Related topics others have asked about: