HEAVY SPOILERS, PLEASE READ WITH CAUTION.
Adam: In the Bible, Adam is the first man and husband of Eve. In Eva, Adam is a 'Giant of Light', discovered in Antarctica, that bears a striking resemblance to the Evangelions. He was awakened using the Super Solenoid Theory, and when humans tried to introduce DNA into his body using the Lance of Longinus the growth went out of control and Adam had to be reduced to an embryonic state before the other Angels awoke to minimise the potential damage. This resulted in the Second Impact. Adam's embryo was later grafted onto Gendo Ikari's right hand.
Angel: The biblical definition is that of a messenger sent from God; in Eva, Angels are mysterious creatures with immense destructive power, their size ranging from the enormous to the microscopic. They all share the ability to generate an AT field, and the presence of an S2 organ.
AT field: This stands for 'absolute terror field'. This is a barrier that an Angel or Evangelion can create around itself to protect it from harm. Only an Angel, an Eva or the Lance of Longinus is able to break through it. Alternatively, a well-aimed power beam can be used; this was demonstrated by the positron rifle used to destroy the fifth Angel. It required the whole electrical supply of Japan to be successful, however. In Episode 24, Kaworu Nagisa describes the AT field as "the light of one's soul", and hints that all humans have an AT field as well. In EoE, the breakdown of humans' AT fields leads to their bodies physically disintegrating.
Black Moon: See the Egg of Lilith.
Central Dogma: The control centre of NERV, in which the main control room is located. It is named after the Central Dogma of Genetics, which outlines the process of DNA giving rise to RNA, and RNA to proteins.
Children: The individuals, born in the year 2000, who were chosen to be designated Evangelion pilots according to the Marduk report. The first to be chosen is the First Child (sometimes mistranslated from Japanese as the plural), the second to be selected is the Second Child, and so on. They are all of the same age (being born soon after Second Impact) and all have lost their mothers prior to piloting.
Complimentality: See Human Instrumentality. Also known as the 'Human Complimantality Project'.
Dead Sea Scrolls: The mysterious documents SEELE uses to predict and plan Instrumentality. The real life Dead Sea Scrolls were discovered in a cave in the Middle East in 1948, and include versions of everal religious documents, including parts of the Bible.
Dummy plug: The system used by NERV to control an Evangelion Unit by remote control if the pilot is somehow incapacitated. The dummy plugs in Units 00-02 contain clones of Rei Ayanami; the dummy plugs in the mass-produced Evas contain clones of Kaworu Nagisa.
Egg of Lilith: The Source of all human life, and the place where all souls go when Instrumentality takes place. Its shell forms the outline of the Geofront and is also known as the Black Moon.
Entry Plug: The metal tubelike container that houses the Evangelion pilot, inserted into the Eva Unit's spine. It is filled with LCL, which allows the pilot to synchronise.
E-Project: Also known as 'Project E', this was the project dedicated to building the Evangelions, in secret. It was started by the organisation Gehirn, and continued by NERV.
Evangelion: A giant humanoid multi-purpose combat weapon designed to combat the Angels. They are equipped with thick armour, an AT field and a range of weapons including progressive knives, rifles, axes and spears. Unit 01 was cloned from tissue taken from Lilith, while the rest were cloned from tissue taken from Adam. It later turns out that they were also built to aid the Instrumentality Project.
First Impact: Also known as the Giant Impact, this was the catastrophic event which wiped out the dinosaurs and many other species on Earth around 65 million years ago.
Gehirn: This is the organisation under the control of SEELE, which was responsible for the building of NERV headquarters and the MAGI, and the E-project. It was later disbanded and all surviving employees were re-employed to form the agency NERV. 'Gehirn' is German for 'brain'.
Geofront: The giant spherical concavity in the ground underneath Tokyo-3. It is several kilometres wide, and contains forests, lakes and NERV headquarters. The ceiling consists of several layers of armour to protect it from attack. In EoE, it is discovered that the geofront is in fact the Egg of Lilith, or Black Moon.
Human Instrumentality Project: Also known as the Human Complimantality Project, Instrumentality is the project that aims to merge all human beings into one single entity. This involves the breakdown of AT fields, and will result from Third Impact.
Lance of Longinus: In the Bible, this was the spear belonging to a Roman soldier that pierced the side of Christ on the Cross. Also known as the Spear of Destiny, it is an important holy Relic which reputedly gives its owner the power to rule the world. In Eva, it is a two-pronged spear with a double-helical handle that can pierce anything, including AT-fields. It is also vital to the success of the Human Instrumentality Project. The mass-produced Evangelions are equipped with copies of this Lance.
LCL: The yellow, bloodlike fluid used to fill the entry plug of the Evangelions, and is found in large quantities in Terminal Dogma. Contrary to popular belief, LCL does NOT stand for Link Connection Liquid. When the entry plug is full of LCL, it allows him or her to breathe by transporting oxygen to the lungs. When LCL in the entry plug is electrolysed it allows the pilot and the Eva to synchronise.
Lilith: In Jewish mythology, Lilith was the first wife of Adam, but when Adam voiced his dissatisfaction with her, God cast her out of he Garden of Eden and created Eve instead. Lilith then roamed outside the Garden, and is believed to be the mother of all demons. In Eva, Lilith is the being from whom humanity is descended. She is kept in Terminal Dogma, nailed to a red cross with a mask resembling the seven-eyed logo of SEELE covering her face. The blood of Lilith, LCL, is used for several purposes by NERV, such as in the entry plugs of the Evangelions.
Magi: The three supercomputers housed in Central Dogma in NERV headquarters. The thought patterns of their creator, Naoko Akagi, were uploaded by transplant OS, and as a result they contain the three aspects of her soul: as a scientist, a mother and as a woman. They are in charge of NERV HQ, many operations in Tokyo-3 and operation of the dummy plug system, should the need arise. The Magi were the three wise men of the East in the Nativity. Because of this, the three computers are named after them: Caspar, Melchior and Balthazar.
Marduk Institute: The organisation, later found to be under control of NERV, which was set up to carry out the selection of Children for piloting the Evangelions. References to the Marduk Report are concerned with choosing the pilots.
NERV: The agency in charge of operating and maintaining the Evangelions, and fighting the Angels. It was formed as a result of the dissolution of Gehirn, and although it appears to be under the control of the Japanese government and/or the UN, NERV is actually a branch of SEELE. 'NERV' is German for 'nerve'.
Old Tokyo: The original capital of Japan, which was destroyed by Second Impact. The seat of government was then moved to Tokyo-2.
Operation Yashima: The plan devised by Lieutenant (later Major) Misato Katsuragi, to destroy the Fifth Angel. It involved the use of a high-power positron rifle fired at long range, which had sufficient power to penetrate the Angel's AT-field. In order to achieve this, the entire electricity supply of mainland Japan had to be rerouted to the weapon, stationed outside Tokyo-3.
Progressive knife: Also known as a prog knife, it is the principal close-combat weapon used by the Evangelions. It vibrates at high speed, and slices through materials by breaking them down at a molecular level. Early models, such as those used by Units 00 and 01, consist of a single blade; the prog knife blade of Unit 02 is able to extend to replace the tip if it is somehow broken off.
Second Impact: The global catastrophe which resulted from the act of reducing Adam to an embryonic state. Half of the world's population perished in the climate change, sea level rises and civil unrest which ensued. SEELE misinformed the general public by covering up the truth and claiming that Second Impact was the result of a meteorite hitting Antarctica.
SEELE: The mysterious organisation that controls NERV and the Evangelions. It is also the think-tank that plans and the Instrumentality Project. 'SEELE' is German for 'soul'.
S2 ogan: Also known as an S2 or super-solenoid engine, it is an organ possessed by the Angels which allows them to generate an AT field and also gives them an infinite amount of power and self-repair ability. The mass-produced Evangelion Units were fitted with S2 organs, allowing them to operate without an umbilical cable. Unit 01 also acquired an S2 organ by devouring one of the Angels.
Super solenoid Theory: The theory proposed by Professor Katsuragi, Misato's father. It was proved correct during the discovery and awakening of Adam.
Terminal Dogma: The region of Central Dogma that is buried deep underneath NERV headquarters. It is where Lilith is kept, and is partially-filled with LCL. It is also the location of dummy plug production and storage of failed E-project experiments.
Third Impact: The event which precedes Instrumentality. It was predicted to occur in 2016, according to the Dead Sea Scrolls.
Tokyo-2: The city built after Second Impact, the new capital of Japan, and location of the government which replaced Old Tokyo.
Tokyo-3: The city built on top of the geofront, housing NERV employees and the equipment necessary to maintain and run the Evangelions. During attacks, the buildings in the centre of the city retract downwards into the geofront for protection.
Transplant OS: The method by which a person's soul can be transferred into a mechanical or electronic system. This was used to insert human souls into the Evangelion Units, as well as the Magi.
Umbilical Cable: The electrical cable that is connected to an Evangelion Unit via a socket in its back. The electricity supplied via the umbilical cable provides the enormous quantities of power required by the Eva to function. If the umbilical cable is cut or otherwise disconnected, the Eva's internal batteries give only five minutes of combat time, or sixteen hours in minimal life-support mode.
White Moon: The egg of Adam.