A CCD (Charge-Coupled Device) is an integrated circuit containing an array of linked or coupled capacitors and it is one of two types of sensors used in digital cameras and other optical devices.  The other one being CMOS.

CCDs are considered to the older technology and although most current digital cameras use CMOS sensors they are still widely used and many photographers seek out older cameras with CCD sensors because of their colour and image characteristics.

CCD image sensors are widely used in professional, medical, and scientific applications where high-quality image data is required

CCDs use a global shutter, which exposes the entire image simultaneously. This can lead to blur if any motion occurs in the image during exposure, but a high shutter speed prevents this problem. Whereas CMOS sensors are equipped with ‘rolling shutters,’ which expose different parts of the frame at different points in time. This can lead to skew, wobble and partial exposure in photographs.

CCD sensors create low noise images but consume 100 times more power than a similar CMOS sensor.