A shield is a protective device used to block or deflect attacks, often made of materials like wood, metal, or plastic. Historically, shields were used in combat by warriors to safeguard themselves from weapons such as swords and arrows. They come in various shapes and sizes, often decorated with symbols or designs that represent the owner or their group. In modern contexts, shields can also refer to protective barriers in sports, safety equipment, or even metaphorical uses, such as a "shield" against criticism. Additionally, shields are used in various fields, including law enforcement and military, to enhance safety and defense.