"Digital cinema" is a blanket term for films created with digital technology. When talking specifically about image capture, "digital cinema" refers to cameras that shoot frames-per-second rather than single, compressed video files like most consumer and pro-sumer grade camcorders and DSLRs.
Because digital cinema cameras shoot uncompressed, high-resolution single frames in the style of a traditional film camera, the image files created by digital cinema cameras are known as digital negatives. Digital negatives carry a wealth of light and color information, and are easily manipulated in post-production to change things such as exposure, white balance, color balance, and other aspects of an image without degrading picture quality, as is the case with a camcorder or DSLR image. The Adobe Cinema DNG (Digital Negative) file format has become the industry standard format for digital negatives, however other uncompressed file types, like TIFF, can be used interchangeably.