Antimatter

Antimatter was a generalized term used to describe a state of matter which was different in some significant way from another state of matter. The term applied to any of the following, individually or in combinations:
 * a subatomic particle(protons, quarks, electrons, etc..) of matter with the opposite charge of another particle that has a charge (e.g., an electron);
 * a subatomic particle of matter that is a variant of, but with very different properties of, another particle (e.g., a quark); and/or
 * matter which is physically identical at a macro level to, but exists in a parallel universe from, other matter.

Uses
Antimatter has been used for a variety of purposes. Depending on the type of antimatter in use it can interact, modify, or destroy normal matter. As a result it has been used for everything from a component of weapons of mass destruction, to a fuel source, to scanning technology, to medical uses.

Antimatter and Time
23rd century Federation starships discovered that there was a relationship between some types of antimatter – most notably that used on board – and time. What was observed was that certain controlled implosions of antimatter could result in time disruptions, including travel forward and backward in time. This was experienced in 2266 by the USS Enterprise.

Background
This article does not attempt to explain antimatter solely in the way we understand it in the 21st century. For instance, in the real world antimatter can also be any of: So each of the types of antimatter in the body of the article either is known of today and is consistent with Star Trek, or has been seen in Star Trek and is unknown to or different from 21st century science. For example, today we would say that because it just has mass and directional velocity that the anti-particle of a photon is itself, yet in VOY: "Flesh and Blood" the USS Voyager is able to produce anti-photons from the deflector dish; clearly a different thing in the episode than a regular photon. Also, the anti-particle of an electron is called a positron these days; by the 24th century it seems to mean something else, hence the alternative term "antielectron".
 * a subatomic particle of matter with the opposite linear and angular momentum (which include energy and spin) of another particle that has a linear and angular momentum (e.g., a photon);
 * a subatomic particle of matter with the opposite magnetic moment of a particle that has a magnetic moment (e.g., a neutron);
 * a subatomic particle of matter with the opposite baryon number of a particle.