Trinity College, officially The College of the Holy and Undivided Trinity of Queen Elizabeth near Dublin, is the sole constituent college of the University of Dublin, a research university in Dublin, Ireland. Queen Elizabeth I issued a royal charter for the college in 1592 as "the mother of a university" that was modelled after the collegiate universities of both Oxford and Cambridge, but unlike these affiliated institutions, only one college was ever established; as such, the designations "Trinity College" and "University of Dublin" are usually synonymous for administrative purposes.

A collegiate university is a university in which functions are divided between a central administration and a number of constituent colleges. Historically, the first collegiate university was the University of Paris and its first college was the Collège des Dix-Huit. The two principal forms are residential college universities, where the central university is responsible for teaching and colleges may deliver some teaching but are primarily residential communities, and federal universities where the central university has an administrative role and the colleges may be residential but are primarily teaching institutions. The larger colleges or campuses of federal universities, such as University College London and University of California, Berkeley, may be effectively universities in their own right and often have their own student unions.