Entitlement is the social materialization of owing
To be entitled to something is not the same as to be owed that thing, but there to be a default presupposition that that thing is owed to us.
Consequently, entitlement is not a mental state (or at least, not an individual’s mental state; but some of us know that it makes sense to talk of collective mental states, so entitlement might be one of those kind of mental states) but a social structure or act.
What one is entitled to is a sociological fact, while what one is owed is a moral (and/or political) fact.
To be entitled to something is not the same as to believe that one is owed that thing or to expect to get that thing, but they are closely related:
Entitlement justifies the belief of being owed: Knowing that one is entitled to something justifies believing one is owed that thing, for better (if we are actually owed that thing) and for worse (if we are not),
since justified beliefs can be false, and thus one can be entitled to something one is not owed and vice versa.
Entitlement to things one is not owed is discriminatory, obviously!