Many of these definitions are from Merriam Webster's Collegiate Dictionary (10th edition.) If available, the date the word came into common use is in brackets at the beginning of the entry. This list is not complete. It will be added to as time goes on.

Angel: (11c) Middle English, from Old English engel & Old French angele; both from Late Latin angelus, from Greek angelos, literally, messenger. 1 a: a spiritual being superior to man in power and intelligence b pl: an order of angels 2: an attendant spirit or guardian 3: a white-robed winged figure of human form.
Apparition: (15c) Middle English apparicioun, from Late Latin apparition-, apparitio appearance, from Latin apparEre. 1 a : an unusual or unexpected sight : PHENOMENON b : a ghostly figure 2 : the act of becoming visible.
Astral: (1605) Late Latin astralis, from Latin astrum star, from Greek astronomer. 1 : of, relating to, or coming from the stars 2 : of or consisting of a supersensible substance held in theosophy to be next above the tangible world in refinement.
Athame: Wiccan. Ritual blade used in ceremonies and practices. Used in the directing of energy and, more aptly, making symbolic divisions, the most common of which is the casting of a circle, a cutting out of sacred inner-space in which to work.
BCE: Before Common Era. An alternative dating method corresponding to BC.
Beltane: (15c) Wiccan. Major Sabbat. Celebrated: 15 degrees of Taurus, or May 1. The start of Summer, is the most important Sabbat after Samhain. It is another fertility celebration, but mostly it is a celebration of joy and life. Named for the Celtic fire god Bel, the lighting of fires is a frequent component of Beltane events. A holiday of purification.
Bewitch: (13c) 1 a : to influence or affect especially injuriously by witchcraft b : to cast a spell over 2 : to attract as if by the power of witchcraft : ENCHANT.
Boline: Wiccan. A knife, often white-handled, used for ritual cutting, most often of herbs in preparation for ritual.
Book of Shadows: See Grimoire.
Broom: (11c) Wiccan. Brooms are generally used for purification, used to "sweep clean" an area.
Candles: (11c) Wiccan. Candles are almost always placed at the four compass points of a circle. They may be colored in accordance to the corresponding elements of each point, or they may be a specific color dictated by the purpose of the circle.
Cauldron: (14c) Wiccan. A larger version of a chalice or bowl, largely associated with Wicca thanks to popular myth. Sometimes used to mix potions.
CE: Common Era. An alternative dating method corresponding to AD.
Chalice: (14c) Wiccan. Hold a drink that is passed among the group. Can also be used to simply hold water as a representative of the element of water or as a libation.
Clairaudience: (1864) the power or faculty of hearing something not present to the ear but regarded as having objective reality.
Clairvoyance: (1840) 1: the power or faculty of discerning objects not present to the senses 2: ability to perceive matters beyond the range or ordinary perception.
Conjure: (13c) Middle English, from Old French conjurer, from Latin conjurare to swear together, from com- + jurare to swear. 1 a : to summon a devil or spirit by invocation or incantation b : to practice magical arts.
Conjurer: (14c) 1 : one that practices magic arts : WIZARD 2 : one that performs feats of sleight of hand and illusion.
Cross-quarter days: Wiccan. Sabbats falling between the Solstices and Equinoxes: Samhain, Imbolc, Beltane, and Lughnassadh.
Coven: (1520) Wiccan. An organized group of Wiccans. Sometimes restricted to 13 members.
Demon (Daemon): (13c) Middle English demon, from Late Latin & Latin; Late Latin daemon evil spirit, from Latin, divinity, spirit, from Greek daimOn, probably from daiesthai to distribute. 1 a: an evil spirit b: a source or agent of evil, harm, distress or ruin 2: an attendant power or spirit 3: a supernatural being of Greek mythology intermediate between gods and men.
Demoniac: (14c) Middle English demoniak, from Late Latin daemoniacus, from Greek daimoniakos, from daimon. 1: possessed of influenced by a demon 2: of, relating to, or suggestive of a demon : fiendish.
Demonic: (1662) Demoniac.
Demonology: (1597) 1: the study of demons or evil spirits 2: belief in demons.
Elements: (13c) Wiccan. Air, Water, Earth, Fire and Spirit. A Wiccan’s world is viewed of in terms of four physical elements - earth, water, air and fire (which roughly correspond to the four scientific forms of matter: solid, liquid, gas and plasma) - plus spirit. Together, these elements form a united whole, as is symbolized in the pentagram. All are necessary and should be in balance.
Elf: (11c) Middle English, from Old English ælf; akin to Old Norse alfr elf & perhaps to Latin albus white. 1 : a small often mischievous fairy 2 : a small lively creature; also : a usually lively mischievous or malicious person.
Enchant: (13c) Middle English, from Middle French enchanter, from Latin incantare, from in- + cantare to sing. 1 : to influence by or as if by charms and incantation : BEWITCH 2 : to attract and move deeply : rouse to ecstatic admiration.
Enchantment: (13c) 1 a : the act or art of enchanting b : the quality or state of being enchanted 2 : something that enchants.
Equinox: ( 14c) Wiccan. Around March 22 and September 22, when day and night are equal in length. Held as the sabbats of Ostara and Mabon.
Esbat: Wiccan. A celebration that takes place during the full moon each month.
ESP: (1934) Extrasensory Perception.
Extrasensory Perception: (1934) Perception (as in telepathy, clairvoyance, and precognition) that involves awareness of information about events external to the self not gained through the senses and not deducible from previous experience. Also called ESP.
Fairy: (14c) Middle English fairie fairyland, fairy people, from Old French faerie, from feie, fee fairy, from Latin Fata, goddess of fate, from fatum fate. A mythical being of folklore and romance usually having diminutive human form and magic powers.
Ghost (noun): (12c) 1: the seat of life or intelligence : soul 2: a disembodied soul; the soul of a dead person believed to be an inhabitant of the unseen world or to appear to the living in bodily likeness 3: spirit or demon 4 a: a faint shadowy trace b: the least bit 5: a false image in a photographic negative or on a television screen caused by reflection 6: one who ghostwrites 7: a red blood cell that has lost its hemoglobin.
Ghost (verb): (1606) 1: To haunt like a ghost 2: ghost write 3 a: to move silently b: to sail quietly in light winds.
Ghost Dance: (1890) A group dance of the late 19th century American Indian messianic cult believed to promote the return of the dead and the restoration of traditional ways of life.
Ghost Dance: (14c) Middle English gobelin, from Middle French, from Medieval Latin gobelinus, ultimately from Greek kobalos rogue. : an ugly or grotesque sprite that is mischievous and sometimes evil and malicious.
Goddess worshipping / Goddess spirituality: Pagan religions in which the feminine aspect is dominant. Not Wiccan.
Grimoire: Wiccan. A personal book of rituals, private thoughts, meditations, spells, and anything else dealing with a Wiccan’s experiences. Also called Book of Shadows.
Hag: (14c) Middle English hagge demon, old woman. 1 : an ugly, slatternly, or evil-looking old woman 2 archaic a : a female demon b : an evil or frightening spirit : hobgoblin 3 : WITCH.
Haunt: (14c) 1: to visit or inhabit as a ghost 2:to stay around 3: to appear habitually as a ghost 3: a place habitually frequented by ghosts.
Hereditary Witch: Wiccan. Someone who has passed the skills of witchcraft down through his or her family.
Hobgoblin: (1530) A mischievous goblin.
Imbolc: Wiccan. Major Sabbat. Pronounced “Im’bolc” or “Im’molc.” Celebrated: 15 degrees of Aquarius, or February 1. The beginning of Spring. A holiday of purification, a stripping away of the old in anticipation of the new.
Initiation: (1583) Wiccan. To be formally accepted into a Tradition or Coven.
Litha: Wiccan. Minor Sabbat. Celebrated: Summer solstice (around June 22.) A fire festival. It is a holiday of transition, when the God transforms from young warrior to aging sage. A time for rejoicing, but also of introspection, making sure plans are still on track and correcting negative aspects of one's life.
Lughnassadh: Wiccan. Major Sabbat. Pronounced “loo' na sah” or “loon' sah.” Also known as Lammas. Celebrated: 15 degrees of Leo, or August 1. The start of Autumn. A time of the first harvest, and so this is a holiday of fruition and also of preparation for the oncoming winter.
Mabon: Wiccan. Minor Sabbat. Celebrated: Autumnal equinox (around September 22.) The second harvest, and as such becomes another holiday of thanksgiving. The day when darkness once more overtakes light, and so it is a day of planning, reflection, and the contemplation of mysteries.
Magic: (14c) Middle English magique, from Middle French, from Latin magice, from Greek magikE, feminine of magikos Magian, magical, from magos magus, sorcerer, of Iranian origin; akin to Old Persian magus sorcerer. 1 a : the use of means (as charms or spells) believed to have supernatural power over natural forces b : magic rites or incantations 2 a : an extraordinary power or influence seemingly from a supernatural source b : something that seems to cast a spell : ENCHANTMENT 3 : the art of producing illusions by sleight of hand.
Medium: (1841) an individual held to be a channel of communication between the earthly world and the world of spirits.
Necromancy: (1522) alteration of Middle English nigromancie, from Middle French, from Medieval Latin nigromantia, by folk etymology from Late Latin necromantia, from Late Greek nekromanteia, from Greek nekr- + -manteia –mancy. 1 : conjuration of the spirits of the dead for purposes of magically revealing the future or influencing the course of events 2 : MAGIC, SORCERY.
Neo-Pagan: Another name for pagan.
Ostera: Wiccan. Minor Sabbat. Celebrated: Vernal equinox (around March 22.) A celebration of fertility, conception and regeneration as the earth recovers from winter and begins to bloom. It is also a triumph of light over dark as from now until Litha days will be longer than the nights.
Out-of-Body: (1970) : relating to or involving a feeling of separation from one's body and of being able to view oneself and others from an external perspective.
Pagan: (14c) Middle English, from Late Latin paganus, from Latin, country dweller, from pagus country district; akin to Latin pangere to fix. Follower of an Earth Religion. All Wiccans are Pagans.
Paganism: (15c) Any polytheistic religion or any non-Judeo-Christian religion. However, both of these definitions include such people as Hindus and Amerindians, neither of which associate their religious practices with Paganism.
Paranormal: (1920) Not scientifically explainable. Supernatural.
Parapsychology: (1925) International Scientific Vocabulary. : a field of study concerned with the investigation of evidence for paranormal psychological phenomena.
Pentagram: A symbol of protection and invocation. Always depicted point-up. Symbolizes the union of the five basic elements.
Phenomenon: (1605) Late Latin phaenomenon, from Greek phainomenon, from neuter of phainomenos, present participle of phainesthai to appear, middle voice of phainein to show. 1 plural phenomena : an observable fact or event 2 plural phenomena a : an object or aspect known through the senses rather than by thought or intuition b : a temporal or spatiotemporal object of sensory experience as distinguished from a noumenon c : a fact or event of scientific interest susceptible of scientific description and explanation 3 a : a rare or significant fact or event b plural phenomenons : an exceptional, unusual, or abnormal person, thing, or occurrence.
Poltergeist: (1848) A noisy usually mischievous ghost held to be responsible for unexplained noises.
Precognition: (1611) To know beforehand : clairvoyance relating to an evnet or state not yet experienced.
Psychic: (1642) Greek psychikos of the soul, from psychE soul. 1 : of or relating to the psyche 2 : lying outside the sphere of physical science or knowledge : immaterial, moral, or spiritual in origin or force 3 : sensitive to nonphysical or supernatural forces and influences : marked by extraordinary or mysterious sensitivity, perception, or understanding.
Psychokinesis: (1914) New Latin. : movement of physical objects by the mind without use of physical means.
Psychometry: (1842) : divination of facts concerning an object or its owner through contact with or proximity to the object.
Sabbats: Wiccan. Any one of the 8 holidays. The solstices and equinoxes comprise the minor sabbats. The cross-quarter days make up the major sabbats.
Sage: (14c) Middle English, from Old French, from (assumed) Vulgar Latin sapius, from Latin sapere to taste, have good taste, be wise; akin to Oscan sipus knowing, Old Saxon ansebbian to perceive. Wise through reflection and experience.
Samhain: Wiccan. Major Sabbat. Pronounced “Sow-en.” Celebrated: 15 degrees of Scorpio, or November 1.The Wiccan New Year and the Feast of the Dead. A time to honor and to say goodbye to loved ones who have passed on. A time for reflecting upon the last year, making plans for the upcoming one, and especially for banishing weaknesses or other undesired qualities within.
Skyclad: Wiccan.The practice of doing rituals in the nude. Required in some traditions, but not for all.
Solitary Practitioners: Wiccan. Those who generally practice alone, either by choice or because of a lack of access to appropriate covens.
Solstice: Wiccan. Around December 22 and June 22, when day and night are at their most extreme lengths. Held as the sabbats of Yule and Litha
Sorcerer: (15c) A person who practices sorcery : wizard
Sorcery: (14c) Middle English sorcerie, from Middle French, from sorcier sorcerer, from (assumed) Vulgar Latin sortiarius, from Latin sort-, sors chance, lot. 1 : the use of power gained from the assistance or control of evil spirits especially for divining : NECROMANCY. 2 : MAGIC.
Soul: (11c) Middle English soule, from Old English sAwol; akin to Old High German sEula soul. 1 : the immaterial essence, animating principle, or actuating cause of an individual life 2 a : the spiritual principle embodied in human beings, all rational and spiritual beings, or the universe.
Spirit: (13c) 1: an animating or vital principle held to give life to physical organisms 2: a supernatural being or essence :as a: Holy Spirit b: Soul c: an often malevolent being that is bodiless but can become visible d: a malevolent being that enters and possesses a human being.
Spirit (verb): (1608) To carry off usually secretly or mysteriously.
Spirit Rapping: (1852) Communication by raps held to be from the spirits of the dead.
Spiritualism: (1796) 1: the view that spirit is a prime element of reality 2 a: a belief that spirits of the dead communicate with the living usually through a medium b: a movement comprising of religious organization emphasizing spiritualism.
Sprite: (14c) Middle English sprit, from Middle French esprit, from Latin spiritus spirit. 1 a archaic : SOUL b : a disembodied spirit : GHOST 2 a : ELF, FAIRY b : an elfish person.
Supernatural: (15c) 1: of or relating to an order of existence beyond the visible observable universe : of or relating to God or a god, demigod, spirit or devil. 2 a: departing from what is usual or normal especially so as to appear to transcend the laws of nature b: attributed to an invisible agent (as a ghost or spirit.)
Sword: Wiccan. Used for inscribing a large circle in the ground for large coven rituals.
Telekinesis: (1890) The production of motion in objects without contact or other physical means.
Telepathy: (1882) Communication from one mind to another by extrasensory means.
Tradition / Trad: Denominations of Wicca or Witchcraft.
Wand: Wiccan. Used in directing energy. Wands are often crafted for specific functions, or specific spells.
Warlock: (14c) Middle English warloghe, from Old English w[AE]rloga one that breaks faith, the Devil, from w[AE]r faith, troth + -loga (from lEogan to lie); akin to Old English w[AE]r true. 1 : a man practicing the black arts : SORCERER -- compare WITCH 2 : CONJURER. Male Wiccans and Witches do not use this term.
Wheel of the Year: Wiccan. The cycle of eight sabbats, depicted as a circle. Wiccans view time as cyclical, not linear.
Wicca: (1959) A religion founded by Gerald Gardner. It was strongly influenced by Ceremonial Magic. It also adopted many aspects of Witchcraft, and Wiccans who choose to work magic almost always call themselves Witches instead of Magicians. Witchcraft and Wicca are not synonymous but a person can be both Wiccan and Witch.
Witch: (11c) Middle English wicche, from Old English wicca, masculine, wizard & wicce, feminine, witch; akin to Middle High German wicken to bewitch, Old English wigle divination, and perhaps to Old High German wIh holy. 1 : one that is credited with usually malignant supernatural powers; especially : a woman practicing usually black witchcraft often with the aid of a devil or familiar 2 : an ugly old woman : 3 : a practitioner of Wicca.
Witchcraft: The practice of magic, whether it has religious overtones or not. The practice of low or folk magic. Energy is generally considered to originate in a deity, the earth, objects, or self. Neither good nor evil, but a tool to be employed by the individual wielder. Most Witches have some form of moral code, at the very least a sense of responsibility for all undertaken actions.
Wizard: (15c) Middle English wysard, from wis, wys wise. 1 archaic : a wise man : SAGE 2 : one skilled in magic : SORCERER 3 : a very clever or skillful person.
Yule: Wiccan. Minor Sabbat. Celebrated: Midwinter Winter solstice (around December 22.) A celebration of life emerging from darkness and is honored with the exchange of presents. Evergreens, holly, ivy and mistletoe can be symbolic of the God, still living and green in the dead of winter.
Zombie: (1871) a: the supernatural power that according to voodoo belief may enter into and reanimate a dead body b: a will-less, speechless human capable only of automatic movement who is held to have died and supernaturally reanimated.