Is mettle Connected to Metal?

Originally, mettle was simply a variant spelling of the word metal (which dates to at least the 13th century), and it was used in all of the same senses as its metallic relative. Over time, however, mettle came to be used mainly in figurative senses referring to the quality of someone's character. It eventually became a distinct English word in its own right, losing its literal sense altogether. Metal remained a term primarily used for those hard, shiny substances such as steel or iron, but it also acquired a figurative use. Today, both words can mean "vigor and strength of spirit or temperament," but only metal is used of metallic substances.