the world > physical sensation > sight and vision > optical instruments > mirror > [noun] > metal mirror (3)
A mirror, esp. one used for looking at oneself, typically made of glass with a reflective coating on one side. Cf. glass, n.1 8. Now chiefly archaic…
A mirror made of polished steel, whether an ordinary looking-glass or an optical instrument of some special construction.
As the name of various instruments made of steel. A steel mirror. Obsolete (? nonce-use.)