| ANASAZI | ancestors of the Navajo. |
| APOCRYPHA | "writings or statements of dubious authenticity." |
| AVATAR | ": the incarnation of a Hindu deity (as Vishnu) a: an incarnation in human form b: an embodiment (as of a concept or philosophy) often in a person : a variant phase or version of a continuing basic entity." |
| BEYOND THE SEA | song by Bobby Darin that plays at Scully's parents' wedding and William Scully's funeral. |
| "BLACK CANCER" | Liquid alien that looks like oil, and gain complete control over its host by getting literally under their skin Piper Maru/Apocrypha, Tunguska Terma. |
| BLESSING WAY | ritual performed by Albert Hosteen to heal Mulder. |
| COPROPHAGOUS | "feeding on dung." |
| CSM | Cigarette Smoking Man Cancer Man. |
| DIE HAND DIE VERLETZT | the hand that wounds. |
| DoD | Department of Defense. |
| DOD KALM | dead calm (Norwegian). |
| D.P.O. | Darren Peter Oswald. |
| E.B.E. | Extraterrestrial Biological Entity. |
| ELEGY | ": a poem in elegiac couplets : a song or poem expressing sorrow or lamentation especially for one who is dead b: something (as a speech) resembling such a song or poem : a pensive or reflective poem that is usually nostalgic or melancholy b: a short pensive musical composition." |
| ERLENMEYER FLASK | "a flat-bottomed conical laboratory flask." |
| F. EMASCULATA | F. [Faciphaga] Emasculata is the disease-carrying bug mentioned in that episode. |
| FMU | FBI's Most Unwanted (hummm... who could that be?). |
| GANTA | The Gillian Anderson NeuroTransmitter Association |
| GATB | Gillian Anderson Testosterone Brigade. |
| GETHSEMANE | ": the garden outside Jerusalem mentioned in Mk 14 as the scene of the agony and arrest of Jesus. : a place or occasion of great mental or spiritual suffering" |
| HERRENVOLK | Master race. |
| IDDG | Intellectually Drop Dead Gorgeous (one way to describe Scully). |
| KADDISH | "a Jewish prayer recited in the daily ritual of the synagogue and by mourners at public services after the death of a close relative." |
| LGM | The Lone GunMan. |
| MERCHANDISE | Test subjects whose bodies Mulder finds in a boxcar buried in the desert Anasazi. |
| MIB | Man in Black. Plural: MIBs. |
| MOTW | Monster Of The Week. |
| MPEB | Mitch Pileggi Estrogen Brigade. Contact: [email protected] |
| MPPB | Mitch Pileggi Pheromone Brigade. Contact: [email protected] |
| MUFON | Mutual UFO Network. |
| NICAP | National Investigative Committee of Aerial Phenomena. |
| NISEI | Second generation Japanese-American. |
| OILIENS | see "BLACK CANCER" |
| OUBLIETTE | ". a dungeon with an opening only at the top . to forget" |
| PURITY CONTROL | Name of the cloning project in The Erlenmeyer Flask. |
| QUAGMIRE | ": soft miry land that shakes or yields under the foot : a difficult, precarious, or entrapping position: PREDICAMENT" |
| SPE | SmallPox Eradication. |
| SYX | Smart Young X-Philes |
| SYZYGY | "the nearly straight-line configuration of three celestial bodies (as the sun, moon, and earth during a solar or lunar eclipse) in a gravitational system." |
| TALITHA CUMI | "This is Aramaic for 'Little girl, arise!'" --Wendy Williams |
| TEMPUS FUGIT | Time flies. |
| UNREQUITED | "not requited: not reciprocated or returned in kind |
| UNRUHE | trouble, strife; unrest. |
| UST | Unresolved Sexual Tension. |
| WMM | Well Manicured Man. |
| YAXA | Yet Another X-FILES Acronym. |
| X | The most important letter in the alphabet. |
| YKYAXPW | You Know You're An X-Phile When... |
| ZERO SUM | "of, relating to, or being a situation (as a game or relationship) in which a gain for one side entails a corresponding loss for the other side" |