What is the measurement of alcohol content in liquor referred to as?

The measurement of alcohol content in liquor is referred to as "proof." This term originates from a historical method used to assess the strength of spirits. In the United States, proof is calculated as twice the percentage of alcohol by volume (ABV). For example, if a beverage contains 40% alcohol by volume, it would be labeled as 80 proof.

The concept of proof provides a straightforward and standardized way for consumers to understand the alcohol strength of a beverage. It is commonly used on labels and in advertising, making it an important term within the liquor industry.

Other terms like concentration, alcohol index, and dilution do not specifically refer to the measurement of alcohol content. Concentration could indicate the amount of a particular substance in a solution but is not specific to alcohol. Alcohol index is not a widely recognized term in this context. Dilution refers to the process of decreasing the concentration of a substance in a solution and does not measure alcohol content itself. Thus, the term proof is the most accurate and commonly used measurement for indicating the alcohol content in liquor.