noun
plural coals
[noncount] :a black or brownish-black hard substance within the earth that is used as a fuel
[count] a piece of coal or charcoal especially when burning
b US :a glowing piece of wood from a fire :ember
carry/take coals to Newcastle
Brit :to take something to a place where it is not needed because a large amount of it is already there
haul/rake (someone) over the coals
informal :to criticize (someone) very severely