Large Silver Toned Celtic Triquetra / Trinity Knot Pendant on Green Ball Chain Necklace. According to Wikipedia the definition of Triquetra is: Triquetra (/traɪˈkwɛtrə/; Latin tri- "three" and quetrus "cornered") originally meant "triangle" and was used to refer to various three-cornered shapes. It has come to refer exclusively to a particular more complicated shape formed of three vesicae piscis (the leaf-like shape in between two equal diameter circles when both centers are on the circumference of the other circle), sometimes with an added circle in or around the three lobes. Also known as a "trinity knot" when parallel doubled-lines are in the graph, the design is used as a religious symbol adapted from ancient Celtic images by Christianity. It is similar to Odin's symbol, the valknut.