To determine and to quantify outcome from injury demands that multiple factors be universally applied so that there is uniform understanding that the same outcome is understood for the same injury. It is thus important to define the variables used in any outcome assessment. Critical to defining outcomes is the need for a universal language that defines individual injuries. The abbreviated injury scale (AIS) is the only dictionary specifically designed as a system to define the severity of injuries throughout the body. In addition to a universal injury language, it provides measures of injury severity that can be used to stratify and classify injury severity in all body regions. Its revision, AIS 2005 will be discussed here.