Can I say "during my college years" to refer my university years?
I heard college and university are different.

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In the United States, it would be acceptable since "college" is a generic word with a broader meaning and people who attend a university in the US often say they are "going to college" (for example).

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In Canada, there is a much greater distinction between college and university.

A college is like a technical or trade school where you learn a specialized skill/trade (for a particular occupation/industry) and you do a lot of practical hands-on training in an environment designed to simulate the workplace.

In contrast, a university is an academic institution that provides a much broader (less specialized) education and focuses more on theoretical/textbook knowledge and scholarly research. Most of the learning is done in an academic environment with a combination of lecture and tutorial classes.

Canadians who have attended a university are unlikely to say they went to college and they are unlikely to refer to their time at university as their "college years".

It would be more common to say something like "during my time at university", "throughout my time at university", "while I was at university", "while I was a university student", or "while I attended university".

You could also potentially say something like "during my university life", "during my years at university" , "during my university years"... but these phrases are not quite as natural sounding compared to "during my college years"