copper    
noun uk/ˈkɒp.ər/ us/ˈkɑː.pɚ/
  (METAL)            
 B2 [ U ] (symbol Cu)铜 
a chemical element that is a reddish-brown metal, used especially for making wire and coins
  copper wire/pipes 铜丝/管 
 a copper alloy 铜合金 
  [ U ]红棕色,紫铜色 
the reddish-brown colour of the metal copper
  The copper of Rosie's hair shone in the sunlight. 罗茜的头发在阳光下闪着红褐色。 
  [ C usually plural ] UK informal铜板,铜币 
a brown coin of low value
  I gave him a few coppers. 我给了他几个铜板。 
 - More examples
 - The downward drift in copper prices looks set to continue.
 - Brass is an alloy of copper and zinc.
 - Chemical analysis revealed a high content of copper.
 - They mine a lot of copper around these parts.
 - One of the properties of copper is that it conducts heat and electricity very well.
 
  (POLICE)     
 [ C ] UK informal警察 
a  police officer 
 copper
adjective ukus
 红棕色的,紫铜色的
of the reddish-brown colour of the metal copper