Though in common use, terms such as 'tradition', 'traditional' and 'custom' can in fact be quite hard to operationalise. This is because they are subjective, ambiguous and dynamic. The Torres Strait Treaty and the associated Fisheries Act use terms of this nature. This paper focuses on the word 'tradition' and discusses the two generally accepted views of this, namely a common-sense view of it as a relatively fixed entity, and a more academic view of it as something that may change with circumstances. Neither view of the term allows it to be easily utilised. The paper points out that the language of treaties can also be ambiguous and open to reinterpretation as circumstances change. Accepting this analysis, it is proposed that a way of bringing some precision to such terms is through negotiation between the various parties. Though the paper focuses on the term 'tradition', the findings apply equally to a number of other terms in the Treaty and the Act and these are identified.