Defense contractors are private companies that provide products and services to government agencies, particularly in the area of national security. They may manufacture weapons, aircraft, and other military equipment, or offer support services like logistics and training. These contractors play a crucial role in ensuring that armed forces have the necessary tools and resources to operate effectively. The relationship between defense contractors and the government is often governed by contracts, which outline the terms of service and payment. Major defense contractors include companies like Lockheed Martin, Raytheon, and Northrop Grumman, which are known for their advanced technology and innovation in military applications.