If something appears, it comes into view. Rub a magic lamp and a genie will appear. If that's the case, she will grant you three wishes.
Appear comes from the Latin apparere meaning "to appear, come in sight, make an appearance." Whether literally materializing or seeming to be true, the word appear is used to describe something coming into sight or presenting itself. The word can also be used to describe an actor appearing in a play. Julie Andrews appeared in the musical "Victor Victoria." When someone looks happy, he appears to be happy. When a detail seems true, it appears to be true.