Cloaking device is a ship special in Master of Orion.
The Cloaking Device hides a ship from long-range scans completely. In combat, as long as the ship does not attack, it has a bonus to its defense against beam weapons and a boost to missile evasion. When a cloaked ship does attack, it loses this bonus. Once the ship has attacked, it must remain uncloaked for some time without firing; then it can re-cloak.