The crossword solution for the term 'blemish, as a surface' is MAR, which is an abbreviation for marring. Marring is a type of damage to a surface that causes it to become scratched, dented, or otherwise imperfect. It is usually caused by physical contact with another object, such as a tool or a piece of furniture. Marring can also be caused by chemical reactions, such as corrosion or oxidation.