More properly termed "light cream." It is called "light" because it has a lesser percentage of milk fat than heavy cream. Heavy cream (also called heavy whipping cream) contains 36 to 40 percent milk fat by volume, and light cream normally contains around 20 percent milk fat. If you can only find heavy cream and need a substitute for "light cream," an approximate equivalent would be a mixture of 2 parts heavy cream to 1 part whole milk by volume.