A Glasgow smile (also known as a Chelsea grin/smile, or a Glasgow, Smiley, Huyton, A buck 50 or Cheshire grin) is a wound caused by making a cut from the corners of a victim's mouth up to the ears, leaving a scar in the shape of a smile.[2][3]
The act is usually performed with a utility knife or a piece of broken glass, leaving a scar which causes the victim to appear to be smiling broadly.[4]
The practice is said to have originated in Glasgow, Scotland, in the 1920s and 30s.[5]