Source: A Brief Introduction to Law in Canada (Mar. 2017). p. 265 Middle.
Historically, in Canada, there was debate over rival methods for teaching law. Some members of the legal community believed that traditional English vocational methods for training lawyers should be followed. These methods were based on an apprenticeship model where- by law students served "under articles," and obtained practical experience and direct knowledge of the law by working with and under the supervision of a practising lawyer. This training could also be supplemented with law society lectures. On the other side of the legal education debate were those who favoured the idea of formal university training at a recognized law school, where professors (rather than practising lawyers) taught the law. The debate was resolved in favour of the current model, which combines academic course-work with articling requirements.4
an apprenticeship under a practising lawyer
4 William H Hurlburt, The Self-Regulation of the Legal Profession in Canada and in England and Wales (Calgary and Edmonton: Law Society of Alberta/ Alberta Law Reform Institute, 2000) at 69-78.
How did "article" semantically specialize to this legal signification?