A master (more generically called a head of house or head of college) is the head or senior member of a college within a collegiate university, principally in the United Kingdom. The actual title of the head of a college varies widely between institutions.
The role of master varies significantly between colleges of the same university, and even more so between different universities. However, the master will often have responsibility for leading the governing body of the college, often acting as a chair of various college committees; for executing the decisions of the governing body through the college's organisational structure, acting as a chief executive; and for representing the college externally, both within the government of the university and further afield often in aid of fund-raising for the college. The nature of the role varies in importance depending on the nature of the collegiate university. At loosely federated universities such as the University of London, each college is self-governing and the head of a college acts much like a vice-chancellor. At more centralised universities where colleges are not independent institutions, a college head will have much less power and responsibility.