There are many symbols in the Hindu religion that represent its teachings and gods. Hand and body symbols are called "mudras." Icon symbols are called "murti."
The Aum is a key symbol of Hinduism. It is comprised of the Sanskrit letters that, together, make the phonetic sound that corresponds to the name of the symbol. All Hindu prayers begin with the Aum sound. It is a way of helping Hindus channel their inner spirituality in order to make contact with the gods. Its meaning is "absolute," in reference to the Brahman from which all existence emerged.
Although it has a negative connotation throughout much of the West because it was adopted as the symbol of the Nazis, the swastika is also a very important symbol in Hinduism. The swastika represents eternity to Hindus. It specifically relates to the Brahman as eternal.
The padma, or lotus flower, is the Hindu symbol for freedom or un-attachment. Like Buddhists, Hindus believe that the path to eternal life requires one to let go of all things earthly.
A yantra is a sometimes three-dimensional symbol that represents that universe. Yantras are typically part of ritual and are constructed from multiple types of materials.
Tilaka is a symbol placed on the head of male practitioners of Hindu. The shape of the tilaka indicates whether his devotion is to Shiva or Vishnu.