Cloak is when you hide yourself from everyone.
Official Information Edit
Cloaking is an attempt to manipulate the radiation signature of a ship in such a way that it becomes practically undistinguishable from the natural background radiation of the universe. Accordingly, a cloaking attempt costs 100 Action Points. To attempt to cloak, click on the button in the ship window of the nav screen which reads Cloak (AP:100).
After a successful cloaking attempt your ship becomes invisible on the space chart for other players - unless they occupy the same field. Moving your ship or any other action on the nav screen uncloaks it again.
The chance that a cloaking attempt will succeed depends on four factors:
Field In fields with high background radiation (especially energy fields) the chance to fail cloaking is 12 times lower than in normal space, 8 times lower in asteroid fields and 4 times lower in nebulas. Energy fields are often found in the neighbourhood of wormholes and connection passages between sectors. It is no wonder that these areas can be crawling with cloaked pirates - NPCs as well as players.
Ship size A ship with a bigger size is harder to cloak.
Cloaking Skill A successful cloaking attempt will increase your cloaking skill. A failed attempt will also, but to a much smaller extent. The higher this skill, the higher the chance to successful cloaking.
Cloaking Devices Cloaking devices are available to Union members and to criminals in special hidden places, but in the Federation and Empire this kind of equipment is illegal.
A rule of thumb to remember: When cloaking skill is 10, the probability of successful cloaking in energy fields without a cloaking device is (100-x)%, where x = your ship's size. Checking your cloaking chance is possible without AP costs by clicking Check cloaking chance above the cloak button. Cloaking is almost exclusively used to lay ambushes (normally on enemies or trading vessels carrying valuable commodities) or to hide when on the run. Cloaking also protects from hacks which could determine ones position.
The cloaking boost advanced skill temporary increases cloaking skill.