Typically, when referring to college in the US, people mean university. Universities are made up of colleges (College of Business, College of Arts & Science, Co

Typically, when referring to college in the US, people mean university. Universities are made up of colleges (College of Business, College of Arts & Science, College of Fine Arts, etc). Colleges within universities can have their own admission criteria so if, for example, you started majoring in History and failed all of your classes and wanted to study Finance, the College of Business could reject your application to change majors into their college. However, what usually happens is someone starts majoring in X, eventually realizes that they want to major in Y and there is no problem with them switching.