I’ve googled.
Div is at the heart of the education we offer. It defines the liberal character of Winchester academic life. Pupils engage in discussion and debate, and embrace the idea of learning for its own sake, unrestrained by any examination syllabus. Div refers both to the subject, and to a form of about fifteen pupils from all different boarding houses, whose teacher is referred to as the Div don. Div dons are drawn from the whole range of different academic departments.
Div is multi-disciplinary in scope. In Years 9 to 11, it provides pupils with an introduction to a broad sweep of History, from classical times to the Early Modern period. It also encompasses English literature and language, the History of Science and Art, Religious Studies and PSHEE.