This knot shows that the wearer earned the highest award of Boy Scouting: Eagle Scout. Boy Scouts wear the embroidered rank patch of Eagle Scout.
Scouts wear the Eagle rank emblem centered on the left pocket. Scouters wear the square knot symbol centered above the left pocket.
Where does it all go? See the BSA Insignia Guide for help in placing your Scout insignia and patches in the right place on your uniform.