A pocket veto occurs when the president takes no action on a bill and Congress adjourns. When a bill comes to congress, they have the power to override a veto as long as they have two thirds of the vote within both chambers. If this happens it becomes a law. If congress doesn't allow the bill to return to the floor and adjourn themselves during the ten day time period bestowed on them, and the president does not sign the bill when it comes to him, this is called a pocket veto and the bill does not make it to becoming a law.
