Usually refers to a beautiful flowering plant, the nelumbo nucifera. It's seeds can remain viable for long periods, the longest on record being 1,300 years. The seeds are planted or become embedded in the soil of a lake bed or river, its stem extends to the top (as much as five or six feet) and its leaves and large flowers float on the surface.
Mystically, the lotus has several meanings. The circular flowers are seen as representative of the chakras. The long stem can represent the energy path or nadi that connects the major chakras. The flower is also said to represent transcendence as it shows how the muck at the bottom of the lake can rise to become a beautiful flower. It is also used by Tantric as a term for the yoni, or female genitalia.