A "notch" is a small cut or indentation made in a surface, often used to mark a specific point or to create a fitting. Notches can be found in various materials, including wood, metal, and plastic, and are commonly used in construction, woodworking, and manufacturing. They help in aligning pieces or providing a secure fit. In the context of technology, a "notch" refers to a design feature in smartphones and other devices, where a small cutout is made at the top of the screen to accommodate the front camera and sensors. This design allows for a larger display area while maintaining essential functionality, as seen in devices like the iPhone and Android smartphones.