Framework and libarry are not necessarily mutually exclusive terms. Framework is typically a libarry or a collection of libraries.
Strictly speaking, jQuery is a library, but, to an extent, it does meet the definition of a software framework. Although many would argue that jQuery doesn't meet the definition of a software framework strictly enough, the fact is that no other JavaScript framework fully meets the definition of a framework either.
One of the defining characteristics of a software framework is that its code is protected from modifications. In JavaScript, this clearly isn't the case. Any libraries or frameworks that can be called into your client-side code are modifiable, although it would be against best practices to alter them. Therefore, if it is permissible to call Bootstrap or AngularJS a framework, there is no reason why jQuery cannot be called a framework either. This link contains a more detailed explanation of how jQuery meets the criteria to be called a framework.
Perhaps the best explanation of why jQuery is more of a framework than a library is the fact that as a developer, you can chose not to use any of its framework-like functionalities. You can, for example, mix a simple jQuery statement with a standard JavaScript statement on the same line. AngularJS and Bootstrap typically don't allow you to do this. Therefore, the accurate answer whether jQuery is a framework or not is "it depends whether you chose to use it as a framework or not".
