Put simply, it's 'Digital Cinema'- motion pictures (usually low-budget independents and the odd SPY KIDS or STAR WARS film) that are recorded on some kind of Digital video format, whether it be DVCAM, Mini-DVCAM, Digibeta, HiDef or other.
Theaters expressly tailored to show 'D-Cinema' (such as Landmark theaters which is installing a pile of video projection systems) will be projecting from either a tape or disc format.