A complex crystal which becomes porous to antihydrogen when subjected to a high frequequency elecromagnetic feild of sufficient power. It is used in matter/antimatter reactors in a role analogous to a combination carbaretor and combustion chamber from an internal comustion engine. Simple forms of dilithium occur naturaly but must undergo a complex process to rearange their structures. Most crystals in use are artificially created.

Dilithium has these unique characteristics:

• Available in large quantities on deck 58; unfortunately, we're on deck 7, and an antiproton storm is occupying 37 of the intervening decks.
• Source of limitless power.
• Good guys can only manufacture dilithium in factory planets with trivial static defences.
• Bad guys require slave labour to manufacture dilithium.
• An engineer can convert any dilithium-based device to a power source. Doing so is extremely dangerous, causing large quantities of sweat to pour off said engineer's forehead. However, the hull is never actually breached.
• Dilithium is never found in the same universe as kryptonite.

In Star Trek technobabble dilithium crystals are the thingies that energy is channeled through in order to get it from the matter/antimatter reaction chamber to the warp engines. They can also store some of the energy and be used like a battery. They're kinda like the spark plug of a starship and if they melt, which they often do, the ship ain't goin' nowherez.

Now what's dilithium? Well first off, what's lithium? Well, among other things, lithium hydride batteries are used to power some portable computers and other electronic equipment. So dilithium is just REAL KEWL lithium! Don't snort it though. Makes your nose bleed.