"Amen" is a word that people often say at the end of prayers or when they want to show agreement with something that was said. It's kind of like saying "yes" or "I agree." It's like saying "The end" or "That's all" at the end of a story. It's a way to signal that what was being said is over and that you agree with it. People have been saying "amen" for a really long time, and it's used by lots of different religions and cultures all around the world.