Tarot cards have been around for a long time. There are a lot of theories of how and why they work, but no one really knows. I think they’re just a focal point, or sign posts indicating direction. The real information comes through the reader and the person asking the question (the querent).
There are 78 cards in a Tarot deck. They are divided into two categories, called arcana; 22 major and 56 minor arcana. Our modern playing cards are derived from the minor arcana. Cups became hearts; swords became spades; pentacles became diamonds; and rods became clubs. Knights became jacks, and pages disappeared.
Each card has a meaning that you can look up in a book, but the real meaning comes from intuitive interpretation in the context of the layout. So, the meanings change and can be very personal. I had a friend who ‘programmed’ her cards. For instance, she assigned the meaning of Attorney to the Justice card. So, when that card showed up in a spread, it meant a Lawyer was involved. You won’t find that meaning in any book.