Included in this phenomenon are, inter alia, the definitions of tame, domesticated or wild animals. Most of us intuitively think that wild and domesticated animals are easy to differentiate. But when it comes to giving measurable criteria to accurately discriminate species, there is today no consensus nor tool available. It has become a considerable gap considering that nowadays, challenges related to animal matters require international or global solutions which are only implementable through collaborations across the board and at all scales. However, without accurate and common definitions, those collaborations are rendered impossible. In this research, the etymology and definitions of the phenomenon of Domestication are considered, followed by its evolution across the literature. Are then examined the existing lists of domesticated species. Finally, the use of the concept of this phenomenon is looked at in laws at different scales and through international organisations, highlighting important discrepancies or even contradictions. The result of this research is the ascertainment that adopting a universal definition of the phenomenon of Domestication is absolutely paramount in order to progress on all animal-related matters. These observations and sources are then analysed in order to build the final part of this article: a proposal, aiming at giving an example of what the solution could look like.