The naming conventions for legislation in the United States and the United Kingdom have evolved over time and have undergone various changes and adaptations. It is difficult to pinpoint a specific time when the naming conventions for legislation in the two countries diverged, as the process has likely been a gradual one.
In general, the United States and the United Kingdom both have a long history of using names or titles to identify and refer to legislation. In the United States, legislation is typically given a short and descriptive title, such as the "Patient Protection and Affordable Care Act" or the "Sarbanes-Oxley Act." In the United Kingdom, legislation is often referred to by its short title, which may include the year in which it was enacted, such as the "Companies Act 2006" or the "Bribery Act 2010."
These naming conventions have evolved over time and have been influenced by a variety of factors, including changes in the political and legal systems of the two countries. It is likely that the naming conventions for legislation in the United States and the United Kingdom will continue to evolve and change in the future.