These definitions are from the book "Wicca A to Z, a complete guide to the magical world." by Gerina Dunwich.
All Hallows Eve: Another name for samhain. It is traditionally celebrated on the last day of October.
Almadel: Talisman made of white wax. It is inscribed with the names of spirits or angels and used for cerimonial or "high" magics.
Alraun: A small good luck image (doll) that is shaped from the root of a mandrake or bryony. It is said that it must be dressed daily and offered food and wine. If not it can bring bad luck to the household of the person that has it. The name comes from the Teutonic mythological shape shifting sorceress "Alrunes"
Altar: A raised table or surface in which tools or offerings are placed.
Amulet: A consecrated object inscribed with runes or other magical symbols. They are said to hold powers depending on how they are inscribed or charged.
Anathema: A curse or also an offering to a Pagan deity. Also used in the Roman catholic church to describe the excommunication of heratics.
Angakok: Central Eskimo shaman, medicine man or magician. They use sacred songs, invocations and/or incantations to cure the ill, manipulate the weather and drive spirits from their village.
Angelica: Mystical plant associated with Nordic magic. It was used as a charm to protect the wearer from the black plague. It is said that it guards against evil and black magicks.
Anjara: A witch that appears looking like an elderly woman. It does this to test out the charity of man. Based on hispanic folklore it watches over animals and is believed to possess a golden staff that can transform all it touches into riches.
Animism: The belief that everything is nature, possesses a soul wether animate or inanimate.
Ankh: Ancient Egyptian symbol composed of a cross with a loop for the top. Symbolizes life, common god and goddess, and cosmic knowledge. Aka crux ansata. It is used in spells involving divination, health and fertility.
An-set: Name for a magicians wand.
Apparition: The appearance of a persons phantom. Wether living or
not it is seen in any state as a result of astral projection or clairvoyance.
Astral Body: A double of your physical body. It stays connected to the physical body by an ehteric chord and is not hindered by earthly limitations.
Astral Plane: The place believed to be where we go during astra projection and death. It is believed to be a parallel to this dimension.
Astral Projection: An OBE (out of body experience) that separates the concious from the physical body resulting in an altered state of conciousness.
Astral Twins: Two or more unrelated persons with the same exact birthdate and hour. They are said to have identical personality traits and some similar physical traits as well.
Astrology: The study of the stars/planets and how it effects us.
Athame: Black handled ritual dagger used for gathering and directing energy. It is not to be used to draw blood or cut.
Aura: Light emanated by any living creature. It is cause by electromagnetic energy.
Aureole: A circle of mystical light. Aka "halo"
Autumn Equinox sabbat: Aka Alban Elfed. Occurs on or near september 22. It is a time of thanksgiving, meditation and introspection. Many witches rededicate themselves to their path on this day.
Aziza: Elflike spirits believed to give humans the knowledge of the gods and the powers of magick.