In this paper a terminology for the description of the movement of animal bone in archaeological stratigraphy is proposed and discussed. It is suggested that the terms 're-deposition' and 'residuality' are adopted to describe movement of bone from earlier to later levels, and 'intrusion' and 'contamination' to describe movement from later to earlier levels. While 're-deposition' and 'intrusion' generically indicate movement of bones between different places and layers, 'residuality' and 'contamination' more specifically imply that the bones were found in a phase that was different from the one they were originally deposited in. Consequently, while 're-deposition' and 'intrusion' describe actual physical events, 'residuality' and 'contamination' represent analytical constructs, entirely dependent on the way archaeological phasing is designed. It is suggested that, whether such terminology is adopted or not, zooarchaeologists should be more explicit about the meaning of the concepts they use to describe animal bone movement, and that they also make them as relevant as possible to broader archaeological concerns, rather than merely borrowing from the palaeontological tradition.