Blood alcohol content (BAC), also called blood alcohol concentration, blood ethanol concentration, or blood alcohol level is most commonly used as a metric of alcohol intoxication for legal or medical purposes. Blood Alcohol Content is the legal name for BAC but Blood Alcohol Concentration is sometimes used for simpler description. Blood alcohol content is usually expressed as a percentage of ethanol in the blood in units of mass of alcohol per volume of blood or mass of alcohol per mass of blood, depending on the country. For instance, in North America a BAC of 0.1 (0.1% or one tenth of one percent) means that there are 0.10 g of alcohol for every dL of blood.