To let out means to release or allow something to escape. When you let out your dog in the morning, you open the door so it can run outside. When you let out a sigh of relief after finishing a difficult test, you exhale deeply because the tension is finally over. The phrase suggests something that was held in or contained is now free to go.

The expression has different uses depending on the context. A teacher might let out class early if students finish their work ahead of time. Your pants might need to be let out if you've grown, meaning a tailor loosens the seams to make them bigger. When someone lets out a secret accidentally, they reveal something they were supposed to keep quiet.

Sometimes let out describes a sudden release: a startled gasp, a burst of laughter, or a loud yell. The phrase captures that moment when something inside breaks free, whether it's air from your lungs, students from a classroom, or words you've been holding back.