The Bowen knot (also known as the heraldic knot in symbolism) is not a true knot, but is rather a heraldic knot, sometimes used in heraldic designs. It is named after the WelshmanJames Bowen (who died in 1629) and is also called true lover’s knot. It consists of a rope in the form of a continuous loop laid out as an upright square shape with loops at each of the four corners. Since the rope is not actually knotted, it would in topological terms be considered an unknot.
An angular Bowen knot is such a knot with no rounded sides, so that it appears to be made of five squares. A lozenge-shaped Bowen knot is called a bendwise Bowen knot or a Bowen cross.
When used as a symbol (⌘), an ordinary Bowen knot is known as Looped square, or e. g. as Saint John's Arms.
^Hugh Clark, A Short and Easy Introduction to Heraldry, London 1827, Part 2, Table 3 Bordures Counterchangings & Lines, fig. 7
^ abFrancis Jones: Bowen of Pentre Ifan and Llwyngwair, in: The Pembrokeshire historian journal of the Pembrokeshire Local History Society, No. 6 (1979), p. 40, online here on the National Library of Wales website: “James Bowen … died at Llwyngwair on 22 October 1629 … The main escutcheon borne on the melancholy occasion showed in the first and fourth quarters, azure a lion rampant or within an orle of roses or, in the second quarter gules a chevron or between three true-love knots or, and in the third quarter, azure a bird standing argent.” (emphasis added)