Triquetra (pronounced /traɪˈkwεtrə/) is a word derived from the Latin tri- ("three") and quetrus ("cornered"). Its original meaning was simply "triangle" and it has been used to refer to various three-cornered shapes. Nowadays, it has come to refer exclusively to a certain more complicated shape formed of three vesicae piscis, sometimes with an added circle in or around it. This has been used as a symbol of things and persons that are threefold.
Celtic cultures use the triquetra either to represent one of the various triplicities in their cosmology and theology (such as the tripartite division of the world into the realms of Land, Sea and Sky), or as a symbol of one of the specific triple Goddesses, most notably Brigid, representing the mother, the maid and the crone.
This widely recognized knot has been used in for the past two centuries a sign of special things and persons that are threefold as in Father, Son and Holy Spirit, Past, Present and Future, Mind, Body, and Soul.
Glenn is making our rings of three interlocking bands.
It's great to be marrying a metal man!