In typesetting by hand compositing , a sort is a piece of type representing a specific letter or symbol , cast from a matrix mould and assembled with other sorts bearing additional letters into lines of type to make up a forme , from which a page is printed . In typesetting by hand compositing , a sort is a piece of type representing a particular letter or symbol , cast from a matrix mould and assembled with other sorts bearing additional letters into lines of type to make up a forme from which a page is printed .