The triquetra, also known as a trinity knot, is believed to represent the three promises of a relationship such as to love, honour, and protect, and can be found as a design element on Claddaghs and other wedding or engagement rings.riquetra (/traɪˈkwɛtrə/ ; Latin tri- three and quetrus cornered) originally meant  triangle  and was used to refer to various three-cornered shapes.