What does "metal" mean?

Additional senses

1. 2.A mine from which ores are taken. [Obs.] Slaves . . . and persons condemned to metals. Jer. Taylor.
2. 3.The substance of which anything is made; material; hence, constitutional disposition; character; temper. Not till God make men of some other metal than earth. Shak.
3. 4.Courage; spirit; mettle. See Mettle. Shak. Note: The allusion is to the temper of the metal of a sword blade. Skeat.
4. 5.The broken stone used in macadamizing roads and ballasting railroads.
5. 6.The effective power or caliber of guns carried by a vessel of war.
6. 7.Glass in a state of fusion. Knight.
7. 8.pl. The rails of a railroad. [Eng.] Base metal (Chem.), any one of the metals, as iron, lead, etc., which are readily tarnished or oxidized, in contrast with the noble metals. In general, a metal of small value, as compared with gold or silver. -- Fusible metal (Metal.), a very fusible alloy, usually consisting of bismuth with lead, tin, or cadmium. -- Heavy metals (Chem.), the metallic elements not included in the groups of the alkalies, alkaline earths, or the earths; specifically, the heavy metals, as gold, mercury, platinum, lead, silver, etc. -- Light metals (Chem.), the metallic elements of the alkali and alkaline earth groups, as sodium, lithium, calcium, magnesium, etc.; also, sometimes, the metals of the earths, as aluminium. -- Muntz metal, an alloy for sheathing and other purposes, consisting of about sixty per cent of copper, and forty of zinc. Sometimes a little lead is added. It is named from the inventor. -- Prince's metal (Old Chem.), an alloy resembling brass, consisting of three parts of copper to one of zinc; -- also called Prince Rupert's metal.
8. 9.To cover with metal; as, to metal a ship's bottom; to metal a road.