A dual camera refers to a setup in which a device, such as a smartphone or a tablet, has two separate cameras. These can be used for different purposes and provide additional functionality compared to having just one camera.
One common use of a dual camera is to capture images with both wide-angle and telephoto lenses simultaneously. This allows the user to take photos that include both a broad view of the scene, as well as close-up details without having to physically zoom in or out. Another application for dual cameras can be found in depth sensing technology used for features such as facial recognition, augmented reality and 3D mapping.
In summary, a "dual camera" refers to any device that has two separate cameras working together to capture images with greater detail, flexibility or functionality than would be possible with just one lens alone.