mettle

The word 'mettle' is an orthographic variant of 'metal,' sharing its ultimate Greek origin in metallon, meaning a mine or quarry. In the 16th and 17th centuries, the spelling 'mettle' was adopted specifically for the figurative sense, drawing an analogy between the inherent strength, durability, and quality of a metal and the innate character and spirit of a person. This semantic evolution represents a classic process where a concrete, physical noun is metaphorically extended to describe an abstract human quality, solidifying in English as a term for resilient courage and fortitude. The distinct spelling helped crystallize the abstract meaning separate from its material source.

This word is a simplex form. It is a variant spelling of the word "metal," which entered English from Old French metal, from Latin metallum (mine, mineral, metal), from Greek metallon (mine, quarry, metal). The semantic shift from a physical substance to a quality of character is a figurative development within English.