Abstract
Fifteen years ago Casteel and Grayson (1977) identified potential ambiguity in the definitions of quantitative terms and units used by zooarchaeologists. As solutions they suggested that analysts use the original definitions of terms and explicitly specify how units are counted. The history of zooarchaeology since then has involved a shift from producing estimates of taxonomic abundances to measuring various taphonomic processes and effects within taxa. As a result, many new quantitative units and terms for those units have been proposed. Some of these new units and terms have been used to measure properties of bone assemblages that are not clearly related to a taphonomic process or effect. Other units and terms have been used inappropriately due to apparent misunderstanding of the property measured by a unit or due to some assumed, implicit meaning of a term. The 112 terms compiled for this study have 122 distinct definitions. Some of the designated quantitative units are synonymous with one another while other units are used in ambiguous manners that seriously compromise their reliability. Explicit definitions of quantitative units and terms along with detailed descriptions of how individual units are measured are mandatory to the efficient communication of research results and the continued prosperity of zooarchaeological research.