A Square knot is referred to as “Square” because of its shape. It is symmetrical across the midline.  A square knot is composed of two overhand knots turned in opposite ways. 
An early reference of the name “square knot” is found in Dana’s 1841 maritime compendium A Seaman’s Friend, which also gives “reef knot” as an alternative name.


 

Read more about Surgical Knotting Techniques: https://worldsurgeryforum.net/2022/03/surgical-knotting-techniques.html