The term 'The Real McCoy' (The Genuine Article) is an idiom that originated in the late 19th century. It is used to refer to something that is genuine and authentic, and not a copy or imitation. The term comes from the name of a Scottish-American engineer and inventor, Elijah McCoy, who was known for his inventions of lubrication devices for steam engines. His products were so reliable that they became known as 'the real McCoy, ' and the phrase has since been used to refer to anything that is genuine and authentic.