Arani (Sk.). The “female Arani” is a name of the Vedic Aditi (esoterically, the womb of the world). Arani is a Swastika, a disc-like wooden vehicle, in which the Brahmins generated fire by friction with pramantha, a stick, the symbol of the male generator. A mystic ceremony with a world of secret meaning in it and very sacred, perverted into phallic significance by the materialism of the age.
Source: H.P.Blavatsky - The Theosophical Glossary