They seem to interchange college and university. College,as I know, means two-year course school or a part of the whole university such as Art College, Engineering College, etc.But it also seems to mean a university in expressions like "When I was at college, I studied very hard". So does the meaning vary depending on context?
Also, is the following correct?
Where did you go to university? = Which university did you attend?
Technically, in American usage, a university is comprised of several colleges. However, in both spoken and written expression, as well as in how some institutions name and advertise themselves, this distinction is blurred and ignored.
In American usage, 'college' is the word used to refer to a four year period of advanced study that concludes with the reception of a bachelor's degree. 'College' in this usage means both university study and collegiate study. When an American says, 'I went to college in Boston,' he may mean that he attended Boston College or Boston University. It is not common in American usage to say, 'I attended university.'
The question, 'Where did you go to college,' asks which college or university a person attended, not its geographical location. If you ask an American, 'Where did you go to college,' and he replies, 'Indiana,' he means he attended Indiana University, not that he attended one of several universities located in Indiana. An American would never ask, 'Where did you go to university?'