There are two domains that are commonly associated with sites that owned by a university or college: .edu and .ac.
In the case of .edu, it is only available for United States higher education institutions or higher education institutions outside U.S that are affiliated with the United States since 2001.
For non-U.S colleges and universities, they will commonly use .ac as a second-level domain before putting in their country domain as the top-level domain. Examples of this would be .ac.uk and .ac.jp.