The quantitative determinations of bone, fat and muscle in meat animals have varied with the availability of facilities and personnel. Obviously, evaluations that vary from complete chemical analyses of the carcass to the use of a few linear measurements, which are based upon correlations become difficult to interpret and compare. The tremendous biological variations in carcass traits make it difficult to use linear measures to accurately estimate carcass compositions. However in many instances, under the conditions available for carcass evaluation, these measurements are the only evaluations that can be obtained. Before discussing methods for evaluating carcasses, an attempt will be made to define terms used by meat researchers for describing carcass data. Much of the terminology in use has been accepted without questioning either the definition of the terms or the need for standardizing procedures for the purpose of comparing research results. Certain of the definitions set forth are well