What is "stand down"? I have only heard of "stand up".

Native speaker’s answer
Rebecca
This actually term that means to go off duty or relax from a state of readiness, particularly in a military situation. Generally when used it's asking people to stop and aggressive action or to stop trying to escape. You will usually hear it the movies used by police or soldiers. Ex: Stand down. We have you surrounded. Ex: Stand down soldier. You won't win this fight.