the unit of measurement for the proportion of gold in an alloy; 18-karat gold is 75% gold; 24-karat gold is pure gold
造句
A unit of measure for the fineness of gold, equal to 1/24 part. Pure gold is 24 karat; gold that is 50 percent pure is 12 karat. 開測量黃金純度的單位，等于24等分中的一分。純金為24開; 50％純度的黃金為12開。