CID (Compact Iodide Daylight)

A high intensity discharge lamp that produces a light similar in colour temperature to daylight (approx. 5500K). A 1000W CID lamp produces 2.5 times more light than a 2000W tungsten halogen source. (source: Theatrecrafts.com)

Quoted from Blue Room entry by niclights in topic 'MSR, MSD etc differences'.