A college (Latin: collegium) is an educational institution] or a constituent part of an educational institution. Usage varies in English-speaking nations. A college may be a degree-awarding education educational institution, an institution within a federal university, an institution offering vocational education, or a secondary school.
In the United States and the Republic of Ireland, "college" and "university" are loosely interchangeable, whereas in the United Kingdom, Australia, Canada and other Commonwealth countries, "college" may refer to a high school, a college of further education, a training institution that bestows trade qualifications, or a constituent school within a university.
Adapted from Wikipedia