"The Vesica Piscis is made by linking two cicles together, bringing the outside edge of each to the midway point of the other. The almond-shaped center of the image is called a mandorla (Latin for almond; "vesica" or "vesica piscis" is sometimes also used to describe only this almond-shaped center.) The mandorla can easily be seen as a grail or chalice, connecting the symbol to Avalon."

Source : Philomuse