This is a term used when reading Tarot cards, or any other cards, such as angel cards.
A card is said to be upright when the images on the card are faced right-side-up. When reading playing cards, or even some of the older-style Tarot cards, sometimes it is hard to tell from just the pips on the card whether it is upright or reversed.
The upright meaning is the primary meaning of the card. A card that is upright is also said to be dignified.