Some say the apple is a very rich symbol. Temptation is the first one that springs to mind. A very rich, and very old, image is that of a skeleton holding an apple.
Others say apples is symbolic of immortality and reincarnation. Along with the pomegrante, it represents the cycle of life, death and rebirth.
In many tales the Apple is the World Tree, the axis of the worlds, and it is often a doorway to the realms of Faery, being associated with the Isle of Avalon.
Apples were often given as gifts to humans by the gods, and apples are sometimes believed to confer psychic power.. As a symbol of beauty, the Apple of Discord was to determine the most beautiful of the goddesses, and thus started the Trojan war.
The fruit of the apple trees are associated with health, for their abundance of medicinal uses, from cleansing the teeth to relieving indigestion, to releiving fevers and much more.
Apple trees grow abundant fruit, and thus it is also associated with the principles of generosity and abundance. It is symbolic of love and fertility, and is considered an approdesiac.
Yet another interpretation is that apples signify liberality, felicity, peace, and salvation. Fruit of all kinds was considered to be evidence of God's kindness and a symbol of the goodness of providence.