A "shield" is a protective device used in combat to block attacks and defend the user. Traditionally made from materials like wood or metal, shields come in various shapes and sizes, often carried by warriors such as knights or Roman soldiers. They not only provide safety but can also be used to display symbols or designs that represent a person's family or country. In modern times, the concept of a shield extends beyond physical protection. For example, in technology, a "firewall" acts as a digital shield, safeguarding computers from harmful attacks. Similarly, in everyday life, people use emotional shields to protect themselves from hurtful experiences or criticism.