the art of rubbing a soft pencil or chalk on a piece of paper placed over a brass in a church; the pattern you get by doing thisSee related entries:Artwork and techniques,Crafts and skillsCultureBrasses are large flat pieces of decorated brass(= a shiny yellow metal) which have been put in the walls and floors of churches in memory of dead people. Most brasses were put into churches from the 13th century to the 17th century, and usually have designs cut into them representing the dead person. People make their own copies by covering the brass with paper and rubbing the paper with coloured chalk or wax.
See brass rubbing in the Oxford Advanced American Dictionary