What does the term "proof" indicate in a liquor?

The term "proof" refers to the measurement of the alcoholic strength of a liquor. Specifically, proof is defined as twice the percentage of alcohol content in a beverage. For example, a liquor that is 40% alcohol by volume (ABV) would be 80 proof. This measurement helps consumers understand the potency of the liquor they are drinking, which can affect how it is served, consumed, and mixed with other ingredients.

Understanding proof is particularly important for bartenders and consumers alike, as it influences not only the drink's strength but also its potential effects. It does not provide any information about the age, type, or flavor profile of the liquor, making it a specific indicator of alcohol content rather than a comprehensive assessment of the beverage.