copper
銅 centers on the metal copper, a reddish-brown element used for wiring, coins, and alloys.
銅 combines the metal radical 金 with 同, which likely contributes the sound ドウ. The character originally referred to copper as a specific metal.
The left side 金 means metal, and the right side 同 looks like a container. Picture a metal container made of shiny reddish copper.
For ドウ, imagine a copper dome: dome -> ドウ, and the dome is made of gleaming copper metal.
copper (Cu)
bronze statue
bronze medal
copper coin
bronze
copper mine
bronze ware
shakudo; gold-copper alloy, often with a blue patina
gong; tam-tam
brass
bronze prize; bronze award; bronze medal; third-place prize
bell-shaped bronze vessel of Yayoi period
sheet copper
copper plate; copperplate
copperware
bronze mirror
weight (for scales); counterweight
nickel and copper alloy
cupronickel (alloy of approximately 80% copper and 20% nickel)
beryllium copper