The C# Language Reference on MSDN defines 'protected internal' as "Access is limited to the current assembly or types derived from the containing class". But from a semantic point of view, 'protected internal' sounds to me like 'both protected and internal' which means the member will be accessible only to those derived classes with in the same assembly. Is there any access modifier that has a meaning to the same effect?
C# does not have any such access modifier.
However, the CLR does support it, as the FamANDAssem access level (protected internal is FamORAssem)