Arcana
Arcana is a knowledge type skill linked to Intelligence that can be used to gather knowledge on magical-related topics.
It can be used to recall a useful bit of magic-related knowledge or to recognize a magic-related clue.
Training in Arcana is required to remember knowledge about the Far Realm.
Arcana can also be used to identify creatures from elemental, fey, or shadow origin, or with the construct keyword.0
The Major Arcana are the named or numbered cards in a cartomantic tarot pack, which are the trump cards of a normal tarot pack used for playing card games.
There are usually 22 such cards in a standard 78-card pack, typically numbered from 0 to 21.
Arcana can also refer to either of the two groups of cards in a tarot pack, the major arcana and the minor arcana.1
In alchemy, arcana means "a secret, a mystery" or "the secret virtue" of anything.2