met·al (mtl) KEY
met·aled, also met·alled met·al·ing, met·al·ling met·als, met·als
Middle English, from Old French, from Latin metallum, from Greek metallon, mine, ore, metal
In modern English, metal and mettle are pronounced the same, and they are in fact all related. Middle English borrowed metal from Old French in the 14th century; Old French metal, metail, came from Latin metallum, from Greek metallon, "mine, quarry, ore, metal." By the 16th century, metal had also come to mean "the stuff one is made of, one's character," but there was no difference in spelling between the literal and figurative senses until about 1700, when the spelling mettle, originally just a variant of metal, was fixed for the sense "fortitude." The history of English has numerous examples of pairs of words, like metal and mettle, that are (historically speaking) spelling variants of the same word; two other such pairs are trump/triumph and through/thorough.