There are many varieties of Tarot decks, and there is no standard number of cards across all decks. While the types of cards, the suits and their meanings are the same, the illustrations vary greatly. Decks are based on various themes such as nature, animals, fantasy, dragons, etc. The most common deck in the United States is the Rider-Waite deck, which was created in 1909 by A.E. Waite, a prominent member of the aforementioned occult group The Hermetic Order of the Golden Dawn, and published by Rider & Company. The artist was Pamela Colman Smith. This 78-card deck was the only readily available deck in the United States for many years, which is why some consider it the "definitive" tarot deck in the U.S.
The Tarot deck is made up of the minor arcana and the major arcana. Like regular playing cards, the minor arcana of the Tarot deck includes four suits. Rather than spades, hearts, diamonds and clubs, however, the suits are wands, swords, cups, and circles or pentacles
Each suit has meaning regarding a specific approach to life. The cards within these suits are numbered one through 10 and also include the court cards — the king, queen, knight and page. The minor arcana cards represent the more minor, practical daily ups and downs in life.
The major arcana are not associated with the suits. They include the picture cards that represent principles, concepts and ideals. They are numbered one through 21, with the 22nd card (the "Fool") marked as zero. The major arcana cards represent strong, long-term energy or big events in some area of life.
Seeing a major arcana card about a particular subject in one reading and then getting a minor arcana card about the same subject in the next reading would mean that this subject is becoming less important in your life. To check out various explanations of specific card meanings, see: