spiegeleisen

noun

spie·​gel·​ei·​sen ˈspē-gə-ˌlī-zᵊn 

variants or less commonly spiegel

ˈspē-gəl 

: a composition of iron that contains 15 to 30 percent manganese and 4.5 to 6.5 percent carbon

Word History

Etymology

German Spiegeleisen, from Spiegel mirror + Eisen iron

First Known Use

1855, in the meaning defined above