A watermark in cybersecurity refers to a digital signature, code, or pattern embedded within media files such as images, videos, or documents. This embedded information is usually invisible to the naked eye but can be detected and extracted using specialized tools. Watermarks help identify the original creator or owner of the content, verify authenticity, and track unauthorized distribution. They are widely used to prevent copyright infringement, detect tampering, and combat the spread of fake or altered media. Watermarks play a crucial role in digital rights management and content protection strategies.