[Grammar] in college or a university

[englishhobby]

[FONT=&quot]In a dictionary, I found the following definition of the verb "to major in": to study something as your main subject in college or a university

Why isn't there an article before "college", but there is one before "university"? (in _ college)[/FONT]

 

[probus]

In AmE "college" is very often used as a synonym for university. The indefinite article could have been used with both or with neither. Using it with one and not the other in one sentence seems slightly odd but I wouldn't go so far as to call it wrong.